satishchandra wrote:Recent cosmological advances have made it possible to observe stellar objects that would only a decade ago have been unable to be viewed.

(A) it possible to observe stellar objects that would only a decade ago have been unable to be viewed
(B) it possible to observe stellar objects that would have been invisible only a decade ago
(C) possible that one can observe stellar objects invisible only a decade ago
(D) possible the observing of stellar objects that were not capable of being viewed only a decade ago
(E) possible the observing of stellar objects that only a decade ago would not have been able to be viewed

OA: B

I thought B changes the meaning slightly by changing "unable to be viewed" to "invisible"

Are there any grammatical errors in A?

In A, D and E, unable to be viewed (in A), not capable of being viewed (in D), and that...would not have been able to be viewed (in E) do not convey the intended meaning. The implication of these modifiers is that the STELLAR OBJECTS have an ability affected by the recent advances. The intended meaning of the sentence is that the recent advances have affected OUR ability TO OBSERVE the stellar objects: that the stellar objects were INVISIBLE because WE were unable to see them. Eliminate A, D and E.

In C, have made possible that one is awkward and unidiomatic. Also, possible and can seem redundant. Eliminate C.

The correct answer is B.

Another reason to pick B over A: CONCISION. All things being equal, SHORTER is BETTER. If you're down to two answer choices, and you can't spot an error in either answer choice, select the answer that's more concise.

Nice question buddy. I went for A as well thinking that B changes the meaning.

(B)..due to concision and correct framing of Sub-Verb