Hello ankursethi297,

I would be glad to help you with this query.

Let's take a look at Choice D: the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they

The pronoun they in this choice grammatically refers to neurons, suggesting that the neurons learn new songs. Logically, they must refer to canaries'. But because canaries' appears in this choice in possessive form, the non-possessive pronoun they cannot refer to the possessive noun canaries' because possessive nouns act as an adjective.

Also, this choice seems to suggest that the brain growth in mice is placed in a stimulating environment. This meaning is certainly illogical.


Hope this helps.
Thanks.
Shraddha
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No, a wrong answer cannot be eliminated because of use of "when".

Option D is eliminated not because "when" is used, but because parallelism is lost.

In option D, "when placed in a stimulating environment" comprises of a participle ("placed"), whereas "when they learn new songs" comprises of a clause. D would be better if the last part were as follows: "when learning new songs" (participle instead of clause.)

Moreover "increase in Neurons IN CANARIES" in E (rather than "increase in canaries' neurons)" in D goes better with "brain growth IN MICE"

Another problem with D is that the subject pronoun "they" refers to the possessive antecedent "canaries' "