Although the Contract Called for the Delivery of Three Manuals

Multiple Choice

Although the contract called for the delivery of three manuals, the writer had put so much effort into the first two that the buyer agreed to pay the whole contract price, $3000, for the two instead of the three manuals. Which of the following stops the buyer from later suing the writer for breach of contract and demanding the completion of the third manual?

A) Doctrine of quantum meruit
B) No consideration given by the writer
C) Promissory (equitable) estoppel
D) He only has to pay a reasonable price for the work done.
E) He doesn't have to pay anything because the job was not completed, and so he can even get back what he paid.