Answer:
6 and 12
Explanation:
(b.) is under set A but not set B, meaning that all the elements there are multiples of 3 that are not odd numbers.
all the multiples of 3 that are less than 16: 3 6 9 12 15
all the multiples of 3 that are even numbers: 6 12
thus, the elements that go in (b.) are 6 and 12.
i hope this helps! :D