As a Child, Adrienne Received a Burn from a Campfire

Multiple Choice

As a child, Adrienne received a burn from a campfire and subsequently developed a fear of open flames. As she got older, the fear gradually faded until Adrienne had all but forgotten it. In her late teens, Adrienne was invited to a party at a neighbor's house. As she walked into the backyard, she noticed flames roaring up from a fire pit, and she felt fearful. Her behavior is an example of

A) stimulus discrimination.
B) acquisition.
C) recall.
D) spontaneous recovery.