Sue Buys a Stove from Leons and Is to Pay

Sue buys a stove from Leons and is to pay $300 per month for 15 months. Shortly after she gets the stove Leons tells her that she is to make her payment to the Ace Finance company. Sue is furious and does not want to deal with Ace. Sue sends a letter to Ace saying that she is transferring her debt obligation to her father Donald. As a result

A) Sue must pay Ace as it is a valid novation
B) Donald and Sue are both liable to Ace now
C) Donald must pay Ace as it is a valid assignment
D) Ace can insist payments must be made by Sue and not by Donald
E) Sue only has to pay Leons, since she never made a contract with Ace