Which of the following is the best example of an ethnic category?
a. homo sapienb. caucasianc. kongod. black

Ethnicity is when you are grouped with other people that have the same cultural traditions as you do. Therefore the best answer would be C. Kongo.
The answer isn't B. Caucasian or D. Black because those are races. Those races can be Buddhists, Christians, or Hindu but it doesn't classify them as an ethnicity. 
The answer is C. Kongo because they are members of the Bantu people in the lower Congo River.
Hope this helps!:)

2cool and cold temperature unless its an ever green tree