Which of the Following Best Illustrates the Idea That Doing

Which of the following best illustrates the idea that doing good makes us feel good?

A) Finding money makes people more likely to give money.
B) People are more likely to volunteer their time to help others after they succeed on a challenging task.
C) Donating food to a needy family increases the donor's subjective well-being.
D) Picking up someone's dropped papers is more likely after people recall a happy event.