IMO is E.

This is my explanation:
A. doesn't make any sense.
B. vague.
C. wrong tense. Second half of the sentence is acceptable, not the first.
D. wrong tense. Second half of the sentence is acceptable, not the first.
E. Grammatically correct.

IMO: B

I think the correct answer is E

should tat he had or have fr past activity? is it correct usage here fr have?

Why not B ? Can any one please explain ?

Eiher B or E. B sounds better for me

E is the correct answer.

First, verb forms are consistent.

Second, "it" is complemented in the sentence.

DanaJ wrote:
A, C and D can all be crossed off because we don't know what they "have not already" done. They have not already done what? They must have done something, but what is that something? That's why we definitely need the verb here. Some other reasons to eliminate C and D:

DanaJ, could you please explain this?

If I say "He loves cats, but I don't", people understand that I don't love cats because there is only one verb here, which is "love".

Come back to the question:

If we apply the same principle for A, why can't we understand as "they have not already released"?

Election officials should release the result tomorrow morning, if they have not already (released).

Imo A

Could someone post the OA or the source so I can check the OA?

Thanks

I approached this one with meaning clarity in mind. "The election officials should release the result tomorrow morning" implies that it is something the election officials MUST do rather than something that will happen as per schedule. Hence I am more inclined toward D as it uses the progressive, "should be releasing" which indicates an occurrence that is highly likely to happen. Additionally, the results need not be released all at once, and could be done so in batches, which is the case a majority of times in real life for a variety of reasons(server load balancing etc). Can someone please confirm if the imperative along with progressive is grammatically incorrect by all means acc to the GMAT?

Answer : E

My answer is E

Please suggest a good book for Sentence Correction.

I am very poor at sentence correction.

I think its D. Actually I am confident it is D.
Should be releasing is correct verb usage.

option E