Answer:
The correct answer is 30.
Explanation:
In order to find this, list out the multiples of 6 and 15 and then look for the lowest common multiple.
multiples of 6: 6, 12, 18, 24, 30, 36, 42
multiples of 15: 15, 30, 45, 60
30 is the first that shows up on both