The Law of Evidence

The law of evidence:

A) allows witnesses to testify about things they personally saw or things they were told that others had seen.
B) determines what questions a lawyer may ask, how the questions are to be phrased, what answers a witness may give, and what documents may be introduced.
C) is never as important to the resolution of a case as the underlying substantive law, but still must be strictly followed in order to permit the court to obtain the best evidence possible.
D) All of the above.