A Type II error is defined as which of the following?

A. rejecting a false null hypothesis

B. rejecting a true null hypothesis

C. failing to reject a false null hypothesis

D. failing to reject a true null hypothesis

Option C. failing to reject a false null hypothesis

Step-by-step explanation:

Type II error states that Probability of accepting null hypothesis given the fact that null hypothesis is false.

This is considered to be the most important error.

So, from the option given to us option C matches that failing to reject a false null hypothesis.