Hanson and Taylor Sign a Written Contract for the Transfer

Multiple Choice

Hanson and Taylor sign a written contract for the transfer of Hanson's Foot & Ankle Clinic to Taylor. Hanson claims that the parties later orally agreed to modify it. Any oral modification is likely not enforceable if it falls under

A) the doctrine of promissory estoppel.
B) the "main purpose" rule.
C) the "partial performance" exception.
D) the Statute of Frauds.