A Store Indicates to a Produce Seller, "If You Ship

Multiple Choice

A store indicates to a produce seller, "If you ship me those oranges by Friday, I will consider making you my sole supplier." This agreement is:

A) enforceable because of past consideration.
B) enforceable because it is a preexisting duty.
C) unenforceable because of past consideration.
D) unenforceable because of an illusory promise.
E) unenforceable under promissory estoppel.