Which of the Following Describes Good Practice When Assessing the Validity

Which of the following describes good practice when assessing the validity of any test of hypotheses?

A) Examine the probability model that serves as a basis for the test by using exploratory data analysis on the datA)
B) Test the hypotheses at several different levels of significance.
C) Test both one- and two-sided hypotheses to help guarantee consistency.
D) All of these options are correct.