Question

Choose the alternative that is grammatically correct?

P.S.: Could you please explain to me your answer? And also, why not was considered other alternatives?

a) I will not accept that job offer unless I am told all the benefits it includes
b) I will not accept that job offer unless I will be told all the benefits it will include
c) I will not accept that job offer unless I am going to be told all the benefits it is going to include
d) I will not accept that job offer unless I have been told all the benefits it includes.

Answer 1

I think the correct answer is a), because with the "unless" we use the same verb tenses as with the "if".  

In if clauses we have 4 types and we only use the future in only one type, type 1 (if present simple, future).

So the answer must be future, unless present simple.