According to 2007 Census Data,African Americans Comprise About 12

According to 2007 Census data,African Americans comprise about 12.3% of the U.S.population.Which of the following statements is true?

A) This is the largest proportion in our history.
B) The proportion of African Americans has remained almost the same from the late 1700's to the present.
C) This is smaller than the proportion of African Americans prior to the Civil War.
D) Since slaves were not counted in the census,we do not know how many African Americans lived in the U.S.before the Civil War.