The answer is: A
Explanation
CORRECT OPTION IS A. HALSBURY.
According to Pollock - “Every agreement and promise enforceable by law is a contract”
According to Salmond - “A contract is an agreement creating and defining an obligation between two or more persons by which rights are acquired by one or more to acts or forbearances on the part of others”
According to Sir William Anson – “The law of contract is that branch of law which determines the circumstances in which a promise shall be legally binding on the person making it”
According to Halsbury – “A contract is an agreement between two or more persons which is intended to be enforceable at law and is contracted by the acceptance by one party of an offer made to him by the other party to do or abstain from doing the same act”