Answer: Option D
:
D
I. D is the tallest among C, D & E. But, we don't know anything about A & B. Hence, I is not sufficient.
II. B is not shorter than D, means B is either taller than or equal to D, But, this is not sufficient, as nothing is known about C & E. Combining I & II,
We get that D is the tallest of C, D & E. And B not shorter of A & B. Among B & D it is not known whether they are of equal height or B is taller, which means either B is the tallest in the group or D;