Choice is between D and E. I went with D but not sure why E has been given as an OA.

Experts please help !!
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In later part of sentence it is clearly written.." they have no.. so it should be these animals to correspond to "they"

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Bottle-nosed dolphins have a highly developed sense of taste, enabling them to detect various chemicals in the water, however, since this animal has no olfactory lobe, they apparently have no sense of smell.

1)"Bottle-nosed dolphins" is a plural subject and has a plural verb "have".
2) The verb-ing modifier modifies the entire previous clause i.e. it is an action modifier in this case. Because bottle-nosed dolphins have a highly developed sense of taste, they can detect various chemicals in the water.
3) "However" is a contrast word and "since" is a reasoning word. So in this sentence both are used together that means we have a contrast as well as a reason coming up.
4) Also the pronoun "this" is not correct as the noun it refers to is plural and not singular.


a) since this animal has
b) these animals have.
c) those animals have.
d) since these animals have.
e) since the dolphin has
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