Fred is at a hockey game, and is being bothered by several loud partiers in nearby seats.Fred summons a security guard, who balks at getting involved, but warms up to the idea when Fred offers her $100 to stop the problem.The security guard warns the partiers to knock it off or she'll have them arrested.That works, but then the security guard wants Fred to pay her $100.Fred refuses.Is there sufficient consideration for the security guard to enforce the agreement?

a. No, because of the past consideration rule.

b. No, because of the preexisting duty rule.

c.Yes, because both parties gave something up of legal value.

d. Yes, because there was a bargained for exchange.