in Which set is 2/3 of the numbers composite?

a. 21,29,15,9,27,30

b.18,5,19,33,23,20

c.10,28,21,35,19,11

d.34,12,16,32,22,8

each set ha 6 members, so we want sets with 4 composite numbers.

Small primes are 2,3,5,7,11,13,17,19,23,29,31,37

should be able to tell which are not primes.