Which of the following is false with regard to contract law?
a. If Henry of Vancouver contracts with Carl of Calgary by mail, an important criterion for determining the place of the contract is the place where the offeror lives.
b. An exchange of promises can be consideration adequate to form a contract.
c. To form a contract there must be an offer which is accepted unconditionally.
d. The terms of a contract must be brought to the attention of the offeree before or at the time of contract.