37.
The answer is: A
Explanation
The correct option is A: An agreement enforceable by law.
This is the definition of a contract according to the Indian Contract Act, 1872. A contract is a legally binding agreement between two or more parties that creates and defines their rights and obligations. A contract must have some essential elements, such as agreement, free consent, competency, consideration, lawful object, and not expressly declared as void.
A contract can be classified into different types based on validity, formation, and performance. A contract is different from a mere promise, which is not enforceable by law unless it is supported by some consideration. A contract is also different from an agreement not enforceable by law, which is called a void agreement. A contract is a promise or a set of promises that are enforceable by law.