Secondary colors are
a. the hues red, yellow, and blue, which can be mixed to produce all other hues.
b. hues made by combining equal parts of two primary colors.
c. hues that are directly opposite one another on the color wheel.
d. hues made by combining one primary and one secondary hue.

Well secondary colors are MADE from primary ones, and they are considered "cool" colors, because they are mostly used in cold settings in a portrait/picture. So with that given, your answer would be B, because you combine two primary colors, (like red and yellow), to get a primary color, (like orange). 
I hope I helped, and PLEASE choose my answer as the Brainliest!
Thank you! =D

Ais the correct answer.