How Can Researchers Determine Whether or Not an IQ Test

How can researchers determine whether or not an IQ test is biased against a certain group of people?

A) Measure whether the mean score has been increasing or decreasing over time for members of this group.
B) Determine whether the group's mean score is as high as that of other people taking the test.
C) Examine the questions and decide whether they appear to be unfair to this group.
D) Determine whether members of the group perform better in school than their test scores predict.