Echolocation CR..

[Everything OR Nothing]

Some species of dolphins find their prey by echolocation; they emit clicking sounds and listen for echoes returning from distant objects in the water. Marine biologists have speculated that those same clicking sounds might have a second function: particularly loud clicks might be used by the dolphins to stun their prey at close range through sensory overload.
Which of the following, if discovered to be true, would cast the most serious doubt on the correctness of the speculation described above?
(A) Dolphins that use echolocation to locate distant prey also emit frequent clicks at intermediate distances as they close in on their prey.
(B) The usefulness of echolocation as a means of locating prey depends on the clicking sounds being of a type that the prey is incapable of perceiving, regardless of volume.
(C) If dolphins stun their prey, the effect is bound to be so temporary that stunning from far away, even if possible, would be ineffective.
(D) Echolocation appears to give dolphins that use it information about the richness of a source of food as well as about its direction.
(E) The more distant a dolphin’s prey, the louder the echolocation clicks must be if they are to reveal the prey’s presence to the hunting dolphin.

OA B

I narrowed it down to B and E. But I could not quite eliminate 'E'.
Can you give reasons why 'E' does not weaken the conclusion

[dfs]

Some species of dolphins find their prey by echolocation; they emit clicking sounds and listen for echoes returning from distant objects in the water. Marine biologists have speculated that those same clicking sounds might have a second function: particularly loud clicks might be used by the dolphins to stun their prey at close range through sensory overload.
Which of the following, if discovered to be true, would cast the most serious doubt on the correctness of the speculation described above?

I narrowed it down to B and E. But I could not quite eliminate 'E'.
Can you give reasons why 'E' does not weaken the conclusion

B) The usefulness of echolocation as a means of locating prey depends on the clicking sounds being of a type that the prey is incapable of perceiving, regardless of volume.

B) You need to realize that the sound for stunning the pray is the same as for locating prey, only louder. However, if the prey is unable to hear the click regardless of volume, how the hell is the prey supposed to be stunned by it?
Therefore, B casts serious doubt about the assumption that loud clicks might be used by the dolphins to stun their prey at close range through sensory overload. -> correct

(E) The more distant a dolphin’s prey, the louder the echolocation clicks must be if they are to reveal the prey’s presence to the hunting dolphin.

Here they repeat "loud" and try to confuse you.
But E) only talks about the locating function of the click, not about the hunting function. Besides, even though the dolphin clicks louder, the prey will most likely perceive the click in the same volume because the dolphin is farther away.
Either way, the louder click is not supposed to stun the pray, but simply to locate the pray in the distance.

[RonPurewal]

Hi,
Please read the forum rules. We need the original source of this problem.

Thanks.