Research Examining Frequency of Clefts of the Hard Palate Found

Research examining frequency of clefts of the hard palate found that they were:

A) more common in Asian and American Indian populations than African-derived populations.
B) more common in Caucasian populations than any other racial group.
C) more common in African-derived populations than Asian populations.
D) more common in Caucasian populations than Asian and American Indian populations.