Mrs. Gonzalez baked cookies for her class. After 12 students each ate a cookie, there were 6 left. How many cookies did Mrs. Gonzalez bake?

A. c - 12 = 6; c = 18

B. c - 6 = 12; c = 6

C. c + 12 = 16; c = 6

D. 12 - c = 6; c = 6