请教一道PP题 64

lilyq

Recently documented examples of neurogenesis, the production of new brain cells, include the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that learn new songs.

E

(A) the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that

(B) mice whose brains grow when they are placed in a stimulating environment or canaries whose neurons increase when they

(C) mice's brains that grow when they are placed in a stimulating environment or canaries' neurons that increase when they

(D) the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they

(E) brain growth in mice that are placed in a stimulating environment or an increase in neurons in canaries that

D为何不可？多谢！

AlienX

D的they指代了canaries' neurons
canaries' neurons不能learn songs.