it is related to verb tense - since "Quetzalcoatlus " is still considered to be the largest flying creature in the world, the verb "have been" should be used. - This is an example of Present perfect tense.

modifier question

B - 'and that' there is no parallel that clause
C - 'to have been' refers to past tense which means it is not believed now
D, E - which can not modify the whole previous sentence

I vote for A

what is OA?

I think E is the answer. IMO 'which...' though not accurately but modifies 'the Quetzalcoatlus' in the best possible way that other four options.

Using A makes the sentence sound incomplete.

the answer cannot be E.

the word "which" is used wrong in this sentence

Incorrect: 36 feet, which is believed to be

correct version: flying reptile, which is believed to be

before the word which, you must place the noun or object you are talking about. in this scenario it is the "flying reptile"

if you don't believe me, check it up in the grammar book.

the test takers love to use which in a wrong choice. be careful when evaluating this. do not use your ear for choices with "which"

The sentence is .... Quetzalcoatlus had a wingspan of 36 feet, believed to be the largest flying creature the world has ever seen.

Option A is okay if the latter part of the sentence was qualifying the object "wingspan of 36 feet". But the sentence says "largest flying creature", referring to the Q. Thus I am looking for an option that uses a pronoun before the verb "believed".

"which" and "that" will again qualify the "wingspan of 36 feet" and hence I rule out D and E. B is a little awkward, and I'll settle for C.

Quetzalcoatlus had a wingspan of 36 feet, [u]and it is believed to have been[/u] the largest flying creature the world has ever seen.

Option A, D and E would have been okay if the bird was the object of the former part of the sentence .... eg:
36 feet was the wingspan of Quetzalcoatlus, believed to be the largest ..... .

Hi Guys,
I suggest that anyone who asks a question also provide OA with it but hide the answer. Not having an answer just leads to longer discussions with no outcome

C is the correct answer .
This posts has excellent inputs from all of u ! thanks a lot for discusiing on wider perspectives...


thanks
Senthil