Marys mother agrees to give her a new car if Marymaintains an A average for her

Marys mother agrees to give her a new car if Marymaintains an A average for her senior year of college. Mary does infact earn an A average but when she asks for the car Marysmother tells Mary that she just told Mary that to motivate her andshe will not be getting a car. Mary sued her mother alleging abreach of contract. Who will win this suit?