Final answer:
The most likely cause of action if John sues the physician is an implied contract, which is created by the actions of the patient seeking treatment and the physician providing care, even without an express written contract.
Step-by-step explanation:
If John sues the physician due to damages incurred because of the doctor's care, the most likely cause of action is C. Implied Contract. In the medical context, when a patient seeks the treatment of a physician and the physician agrees to treat the patient, there is often no express contract.
However, an implied contract is created by the actions of both parties: the patient's seeking care and the physician's agreement to provide care. In this case, John filling out medical history forms and the receptionist taking a copy of his insurance card are actions that contribute to establishing an implied contract.
An implied contract is based on the assumption that a service provided will be paid for, which denotes an understanding of mutual benefit and obligation.
This is contrasted with a quasi-contract, which is not a true contract but is a legal substitute formed to impose equity between two parties; promissory estoppel, which refers to a promise that the promisor could reasonably expect to induce action or forbearance on the part of the promisee; and an express contract, which is a clearly stated agreement with explicit terms.