IMO E is correct. It's hard to say but I feel that the second part might be considered independent needing a semicolon...?

SmarpanGamt wrote:The relationship between cell phone use and the incidence of brain tumors is still unclear, this is because some studies show a causal relationship while others do not.

is still unclear, this is because some studies show
is still unclear; some studies show
are still unclear because some studies show
is still unclear because: some studies show
is still unclear; the reason is that some studies show

The first option solves the problem of comma splice by introduction of conjuction. Please explain Y this choice is incorrect. Also explain your bet.

what's the OA?

SmarpanGamt wrote:The relationship between cell phone use and the incidence of brain tumors is still unclear, this is because some studies show a causal relationship while others do not.

is still unclear, this is because some studies show
is still unclear; some studies show
are still unclear because some studies show
is still unclear because: some studies show
is still unclear; the reason is that some studies show

The first option solves the problem of comma splice by introduction of conjuction. Please explain Y this choice is incorrect. Also explain your bet.

Two clauses can be joined in the following ways:

1. Semicolon [;]:

They have done the work; we have won the prize.

2. COMMA + FANBOYS:

They have done the work, but we have won the prize.

3. Semicolon [;] + Conjunctive Adverb + COMMA + Clause:

They have done the work; however, we have won the prize.

4. Period and Capital:

They have done the work. We have won the prize.

5. Subordination:

Though they have done the work, we have won the prize.

That/Because clause as a NOUN clause:

that clause can work as NOUN clause.

Example:
They didn't know that John couldn't swim.
==> They didn't know X. X = NOUN = that John couldn't swim.

This is because they have done it.
==> This is X. X=NOUN=because they have done it.

Now, come to the sentence:
A, C, and D are eliminated because they have not followed the proper rule to join two clauses.

B has followed the rule to join two clauses, but it didn't mention relationship between the clauses by stating cause.

Answer is E.

Thanks.

IMO, it is because it is concise. The part after ";" is understood to be a continuation of thought from the part before ";". In E, "the reasonis that" is just redundant.

agree w/ nox

My doubt on this question is - Whenever there is a conjunction 'and' to join 2 nouns , a plural verb follows. Why is this not the case here??

How do we segregate?

Deepthi Subbu wrote:My doubt on this question is - Whenever there is a conjunction 'and' to join 2 nouns , a plural verb follows. Why is this not the case here??

How do we segregate?

The relationship between cell phone use and the incidence of brain tumors is still unclear, this is because some studies show a causal relationship while others do not.

is still unclear, this is because some studies show
is still unclear; some studies show
are still unclear because some studies show
is still unclear because: some studies show
is still unclear; the reason is that some studies show

@Deepthi,

When the subject is compound subject, then we will use plural verb.Compound subject will have "and" to demarcate between the 2 or more elements.
But here the subject (relationship) is singular. So we are using "is"( singular ) verb.

IMO, B seems to be a better fit then E.

OA [spoiler]"B"[/spoiler]

Source MGMAT Preptest

SmarpanGamt wrote:The relationship between cell phone use and the incidence of brain tumors is still unclear, this is because some studies show a causal relationship while others do not.

is still unclear, this is because some studies show
is still unclear; some studies show
are still unclear because some studies show
is still unclear because: some studies show
is still unclear; the reason is that some studies show

The first option solves the problem of comma splice by introduction of conjuction. Please explain Y this choice is incorrect. Also explain your bet.

The first option does not solve the problem because the conjunction is not actually joining the two independent clauses spliced together. "Because" in the first option is joining what comes after it ("some studies show") with what comes before it ("this is"). The first independent clause ("the relationship is unclear") is still comma spliced to a second one ("this is").

I'd have chosen B. If there had been an answer like D without the colon, that would have been fine also, but more wordy.

How is B better than E.
Can anyone elaborate.

SmarpanGamt wrote:The relationship between cell phone use and the incidence of brain tumors is still unclear, this is because some studies show a causal relationship while others do not.

is still unclear, this is because some studies show
is still unclear; some studies show
are still unclear because some studies show
is still unclear because: some studies show
is still unclear; the reason is that some studies show

The first option solves the problem of comma splice by introduction of conjuction. Please explain Y this choice is incorrect. Also explain your bet.

A is wrong because of Comma splice, two different clauses cant be joined by comma.
C has subject -Verb agreement issue
D is wrong because of use of colon. The connector Because is used to join two clauses but the use of colon makes it incorrect.
E has correct use of semicolon to join two clauses, but E is wordy compared with B. Hence, B is preferred over E.

good question but how gmat perfect's theory doesnt work here.

imo B is better than E only because that E is too wordy comapred to B which is concise

I think that one of the important reasons to use a semicolon between two independent clauses is to avoid subordinator or similar verbose, if they can stand on their own and the relation between them is obvious. So "the reason is that" in the option E may be considered redundant rather than wordy.