Whales make clicking sounds that are strange to human ears, but when those clicks ricochet off objects around the whales, the echoes tell it that there’s a fish to the left, another whale a hundred yards ahead, or a squid in the distance.
A. ears, but when those clicks ricochet off objects around the
whales, the echoes.................in non underline portion 'it' refers to a singular noun. But here 'whales' is plural.
B.
ears, when those clicks ricochet off objects around
the whale; the echoes..............'But' has been removed. 'But' is required here to present a contrast between two equal ideas - how humans feel about the sound vs how whales themselves feel about it.
C. ears, but when those clicks ricochet off objects around
the whale; the echoes.......................the wahle; is wrongly used. Semicolon is used to introduce another independent clause or give an example
D.
ears, when those clicks ricochet off objects around
the whales; the echoes.........Same as B & C
E.
ears, but when those clicks ricochet off objects around
a whale, the echoes..........Seems okay.
IMO OA should be E.