Question

suppose U = {1,2,3,4,5,6,7,8} is the universal set, and P = {1,3,5,7}. what is P'?
a. {2,4,6,8}
b. {1,2,3,4,5,6,7,8}
c. {1,3,5,7}
d. {1,3,5,7,8}