Randy is a firefighter who rescues the Johnson family's cat from a burning building. Since the Johnson family was so grateful, they told Randy that they would give him $10,000 as a reward and put this promise in writing. When Randy comes to collect the next week, the Johnsons tell Randy that they have changed their mind. If Randy sues for $10,000, who wins, and why?

A) Randy, because the Johnson family made a promise in writing

B) The Johnson family, because there is no definite term of when Randy would be paid

C) The Johnson family, because this falls under the past consideration exception

D) The Johnson family, because this falls under the preexisting duty exception