Which of the Following Shows the Use of the Doctrine

Multiple Choice

Which of the following shows the use of the doctrine of promissory (equitable) estoppel?

A) George told Hans that he would give him his printer. If he doesn't, Hans could use the doctrine to force him to do so.
B) George wants to force Elaine to honour her promise to pay him $2. After he paid for a video they watched, she was so moved by the movie she said she would pay half the cost.
C) This doctrine can be used by a plaintiff to endorse a written promise signed and sealed (i.e., a seal has been affixed next to the signature of the promisor) .
D) Lee, a defendant, can use this doctrine as a defence against a plaintiff insisting on his full legal right when he had promised to forgive Lee some of Lee's legal obligation and Lee relied on that promise.
E) If Lam requests services from Jones and there is no mention of price, if Lam doesn't pay Jones, this doctrine can be used to force Lam to pay a reasonable amount.