A Group of Retired Registered Nurses Decide to Volunteer Their

A group of retired registered nurses decide to volunteer their services to a not-for-profit hospital.They perform a variety of tasks,including: (a) filling in for regular nurses when they are out sick; (b) helping out in food preparation;and (c) selling in the hospital gift shop.For which of the three tasks must donated revenues and expenses be recognized?

A) only task (a)
B) only tasks (a) and (b)
C) all three tasks
D) none of the three tasks