Sentence Correction

A President entering the final two years of a second term is likely to be at a severe disadvantage and is often unable to carry out a legislative program.

(A) likely to be at a severe disadvantage and is often unable to
(B) likely severely disadvantaged and often unable to
(C) liable to be severely disadvantaged and cannot often
(D) liable that he or she is at a severe disadvantage and cannot often
(E) at a severe disadvantage, often likely to be unable that he or she can

[spoiler]OA: A[/spoiler]

Why are the wrong options wrong?

Thanks.