Why do hospitals often use wheelchairs to move patients, even when patients are capable of walking?

A Hospital personnel want to make sure patients are waited on and
don't have to do anything for themselves.
B. Patients don't know where they are going in a hospital, and having
personnel wheel them around is more efficient.
C. Hospital personnel do not want to let patients out of their sight
due to the risk of misidentifying patients.
D. Patients may not realize the effect treatment has on their body
and are at risk for falls.