Aimee Is a 21 Year Old College Student

Aimee is a 21 year old college student.Her parents are worried about her being away from home so they tell her that if she goes both the Fall and Spring semesters without drinking alcohol,they will buy her a new car.Aimee does in fact go both semesters without drinking:

A) Aimee gets the car because she performed exactly as required under her parents offer.
B) Aimee gets the car because a quasi contract is formed due to her parent's unjust enrichment.
C) Aimee is not entitled to the car because her benefit far outweighed her detriment.
D) Aimee is not entitled to the car because she's healthier so she suffered no detriment