The fossil remains of the first flying vertebrates, the pterosaurs, ha

Note that the question asks us the author's views.

The author views the idea that the pterosaurs became airborne by rising into light winds created by waves as...

This is what the author says:

Efforts to explain how the pterosaurs became airborne have led to suggestions that they launched themselves by jumping from cliffs, by dropping from trees, or even by rising into light winds from the crests of waves. Each hypothesis has its difficulties.

and then he goes on to explain the difficulty with each hypothesis:
..
..
The third calls for high waves to channel updrafts. The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.

So as per the author, each hypothesis has concerns and hence each is improbable. The issue with the third one is that the wind might have been too strong to control their flight. Hence, he thinks that this hypothesis is unlikely.

Answer (B)

1. It can be inferred from the passage that scientists now generally agree that the

(A) enormous wingspan of the pterosaurs enabled them to fly great distances

From the passage, we know that pterosaurs can fly (It is mentioned in the first para that scientists are intrigued by how pterosaurs solve the problem of powered flights ). Still, nowhere in the passage is it mentioned that pterosaurs can fly to a great distance.

(B) structure of the skeleton of the pterosaurs suggests a close evolutionary relationship to bats
In the last para (it wrongly assumes that the pterosaurs’ hind feet resembled a bat’s and could serve as hooks by which the animal could hang in preparation for flight.), we can infer that pterosaurs are in close relationship to bat

In the third part (The pterosaurs resembled both birds and bats in their overall structure and proportions.), pterosaurs just resembled birds and bats, not in a close relationship.


(C) fossil remains of the pterosaurs reveal how they solved the problem of powered flight
Nowhere in para is it mentioned that pterosaurs solved the problem of powered flights. In the last part, the author has rejected all the hypotheses of how pterosaurs become airborne.

(D) pterosaurs were reptiles
In the second part, it is mentioned that pterosaurs are reptiles (Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. )

(E) pterosaurs walked on all fours
From the passage, we know that pterosaurs has four fingers, but the fourth finger is attached with wings to support the wing-like membrane, and the fourth finger can only turn upward in an extended inverted V-shape along each side of the animal’s body. I will suggest you see the fossil of pterosaurs on Google for a clear understanding.

Could anyone explain 6？Many Thanks！