What Does the Principle of Direct Applicability Mean for EU

What does the principle of direct applicability mean for EU law?

A) Under the principle of direct applicability EU law becomes part of national law of the Member States without the need for it to be transformed into national law by the use of the appropriate constitutional machinery such as an act of parliament, that is, there is no need (as there is in dualist countries like the UK in relation to international treaties) to pass an Act of Parliament to give effect to it. This entails that EU law, being part of national law of a Member State, can be enforced by individuals before the national courts and administrative authorities of that Member State.
B) The rules of EU law are binding on the governments of the Member States.
C) The rules of EU law take secondary importance to the national law of the Member States.