Maria Went on Vacation in May

Maria went on vacation in May. She expected that her garden would be fine because May is normally a very rainy month. In fact, it did not rain at all during May. Her neighbour, Hector, therefore watered her garden because he knew that she would not want her plants to die. When she returned from her vacation in early June, she thanked Hector and promised to pay him $200 for his time and effort. Select the best answer.

A) Maria is contractually liable, but if the market value of her services is less than $200, then Hector is entitled to collect only the lesser amount.
B) Maria's promise is unenforceable because there was no mutuality between her promise and Hector's work.
C) Maria's promise would be unenforceable even if it was placed under seal.
D) The concept of past consideration does not apply because Hector never gave any sort of promise.
E) Maria is contractually liable as long as a reasonable person in her circumstances would have agreed to pay for Hector's services.