Torts are defined by?

a. Common Law Courts, b. Federal Legislation, c. U.S. Supreme Court, d. Administrative Agencies

We are talking definition, not enforcement?
Then the US Supreme Court. The feds may pass the legislation, but the definition is brought into clarity by the supreme court. Common law courts enforce per the definition, they do not define. Administrative agencies are bound by the torts as are individuals.

Torts are Common Law

Common Law Courts

Torts are a wrongful act other than a breach of contract for which relief may be obtained in the form of damages or an injunction. It is handled in a Common Law Court.

Common law court. It has to have diversity of citizens to even get to the Supreme Court, since torts are predicated in state law.

Common Law Courts

(e): all of the above.

primarily common law, but some federal leg (and, i am pretty sure, federal admin regs) create private rts of action as enforcement mechanism. and anytime something is defined by common law or legislation or regs or whatever, the us supreme ct weighs in on it. (in the common law instance it's true that torts are a matter primarily of state substantive law, but that doesn't mean the supreme ct can't apply state substantive law and thus shape it, etc).

All of the above. and more:

Federal, State and local legislatures, federal courts, special(non common law)courts such as a court of chancellery in Delaware, and civil law courts in Louisiana can ALSO create and define torts.