When a Person Observes a Model Engage in an Altruistic

When a person observes a model engage in an altruistic behaviour such as donating to a charity,what effect does it have have on the observer's future behaviour?

A) little effect on willingness to donate, regardless of setting
B) immediate effects on willingness to donate, if assessed in the same setting
C) immediate and long-term increases in willingness to donate, if assessed in the same setting
D) immediate and long-term increases in willingness to donate, even when assessed in a different setting