In Which of the Following Situations Would the Promise Be

Multiple Choice

In which of the following situations would the promise be enforceable as a contractual obligation?

A) "Why don't you come over for dinner on Saturday? I promise I'll cook you a steak and buy a lovely Cabernet."
B) "Thank you so much for supporting me while I received my BA degree, Mom.I promise I'll pay you back every penny you spent on my tuition as soon as I'm gainfully employed."
C) "If you give up cigarettes and alcohol for Lent, I'll pay you $200."
D) All of the above are enforceable providing they are in writing.