While Checking Out at the Pet Store, Diya Is Asked

Multiple Choice

While checking out at the pet store, Diya is asked if she would like to donate to the World Wildlife Fund. She decides to donate $5, and in exchange her name is written on a heart decal that is hung in the store's window. This is an example of the economic concept of:

A) marginal utility.
B) altruism.
C) reciprocity.
D) selfishness.