Studies on the Effect of the Race of the Tester

Studies on the effect of the race of the tester have demonstrated that

A) African-American children consistently score higher when they are tested by African-American examiners.
B) African-American children consistently score lower when they are tested by African-American examiners.
C) White children consistently score higher when they are tested by White examiners.
D) that the race of the examiner does not have a significant effect on the test scores of African-American or White children.