Sentence Correction

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.

a) is still unclear, this is because some studies show
b) is still unclear; some studies show
c) are still unclear because some studies show
d) is still unclear because: some studies show
e) is still unclear; the reason is that some studies show

how to decide b/n semicolon vs comma??
wat is independent and dependant clause

This one I'm not sure about. In general though, you use a semi colon if you are connecting two independent clauses. An independent clause is a clause that has a subject and a working verb. If I had to choose an answer I would choose B, but I'm not sure why E is wrong.

What was the OA?

IMO B. I choose B over E on the grounds of brevity. What is the OA?

osirus0830 wrote:What was the OA?

OA is B
for eliminating OE says the reason is that is unnecessary
so is the problem with a
thanks