Thoughts?

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.

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