Darla Offers to Pay Edward $6,000 for Edward's Car, Provided

Darla offers to pay Edward $6,000 for Edward's car, provided that Darla receives that much from her uncle's estate, which is currently being probated. She expects to know for sure how much she will receive within a week or so. If Edward agrees:

A) there is an illusory contract, because Darla is not certain she will receive the money.
B) there is no consideration present in this example.
C) the consideration from Darla to Edward is the promise of $6,000 subject to a condition.
D) this is an option contract and Edward must wait at least a week for Darla's answer.