Cheryl Hired Golden Construction Co

Cheryl hired Golden Construction Co.to build a house for her.The plans for the house were complex,and expert workmanship was required.After the house was completed,Cheryl liked it so much that she promised to pay Golden a $4,000 bonus.Later,Golden demanded the money,but Cheryl refused to pay it.Golden sues.What is the most probable result?

A) Golden wins; the promise was used to entice Golden to do an outstanding job,which is adequate consideration.
B) Cheryl wins; the promise is based on past consideration.
C) Golden wins; the promise is based on past consideration,which is legally sufficient.
D) Golden wins; the promise is based on changed circumstances which makes it enforceable.