There is a 75% chance that a store will earn a profit of $1,000 and a 25% chance it will lose $2,000 by marking all items half off. Using mathematical expectation, which of the following statements is true?

a. We expect the store to earn a profit of $250 by marking all items half off.

b. We expect the store to earn a loss of $250 by marking all items half off.

c. We expect the store to “break even” by marking all items half off.