What is the concept of Constitutional Law?

A- It is a branch of public law that studies the fundamental laws that define a State.
B- It encompasses everything related to the form of the State, form of government, essential rights and guarantees of individuals, and regulation of public powers.
C- It is the foundation of the legal order of a State.
D- It is the supreme law of a sovereign State, in which the organization and functioning of political institutions are structured and the rights of individuals are guaranteed.
E- All of the above.
a) A and B are correct.
b) C and D are correct.
c) E is correct.
d) Only A, B, and C are correct.