Given below is a statement of legal principle followed by factual situation. Apply the principle to the facts and select the most appropriate answer.
Principle: An agreement becomes a contract when it is entered into between two or more people with each other's free consent. Two or more people are said to consent when they agree to the same thing in the same sence. Consent is said to be free when it is not caused by coercion, undue influence, fraud, misrepresentation or mistake.
A went to a doctor to get himself treated. The doctor asked him to sign a "consent form" and said that unless he signs it, he will not examine him. A signed the form waiving his right to sue the doctor.