If you receive a free ticket to a concert, what, if anything, is your opportunity cost of attending the concert?

A$.$ The pleasure yielded by the concert cancels any costs. Thus, there is no cost of any type.

B$.$ The next best activity that can't be done while attending the concert.

C$.$ The concept of opportunity cost does not apply to intangibles like concerts.

D$.$ Since the ticket was a gift, there is no opportunity cost.

During her years of college, Dominique discovered that her three favorite subjects were astronomy, chemistry, and political science. She chose to major in astronomy because she had seen data indicating that science majors earn higher$-$than$-$average wages and because she liked astronomy better than both chemistry and political science. Upon graduation, however, she learned that average wages in chemistry fields were $20$ percent higher than average wages earned by astronomers. Did Dominique's behavior violate the rationality assumption?

Dominique's decision to major in astronomy

A$.$ did not violate the rationality assumption because her actual wage working as an astronomer could be higher than the average wage in chemistry fields.

B$.$ did not violate the rationality assumption because she preferred astronomy, and because, at the time she made her decision, data showed science majors earn higher$-$than$-$average wages.

C$.$ did violate the rationality assumption because average wages in chemistry fields are $20$ percent higher than average wages earned by astronomers.

D$.$ did violate the rationality assumption because she made her decision without comparing average wages in chemistry and astronomy fields.