How Would a Neurobiologist Working with Songbirds Probably Answer This

Multiple Choice

How would a neurobiologist working with songbirds probably answer this question: "Does the brain have the ability to develop new neurons?"

A) No,the brain has its full store of neurons at birth.
B) Yes,the brain constantly generates new neurons as old ones die off.
C) No,neurons increase dendritic branching and form new connections only,Not new neurons.
D) Yes,the brain is capable of generating new neurons in response to hormonal variation.