Jen spends her afternoon at the beach, paying $1 to rent a beach umbrella and $11 for food and drinks rather than spending an equal amount of money to go to a movie. Her opportunity cost of going to the beach is

a. the value she places on seeing the movie.

b. only $0 because she would have spent $12 to go to the movie.

c. the value she places on seeing the movie plus the $12 she spent on the umbrella, food and drinks.

d. the $12 she spent on the umbrella, food and drinks.