Delegated legislation is specifically the exercise of law-making power by executive or administrative bodies under authority delegated by the legislature through a parent statute. Option (a) is too narrow (local government legislation is one type, not the definition). Option (b) describes primary legislation, not delegated. Option (d) describes judicial/quasi-judicial decisions, not legislation. The key element is the delegation chain: Parliament passes the parent Act → empowers the executive to make detailed rules within the Act's framework.