The correct option is A Constitutional law
A democratic government cannot do whatever it likes simply because it has won an election. Every major decision has to go through a series of consultations. Every office bearer has certain rights and responsibilities assigned by the constitution and the law. A democratic government rules within limits set by constitutional law and citizens rights. Hence, Option A is correct. The rest of the options are groups who are all governed by the Constitution, the supreme law of the society. Hence, these are incorrect.