List the next nine multiples of 6, starting with 24
a. 24, 30, 36, 42, 48, 54, 60, 66, 72
b. 24, 28, 32, 36, 40, 44, 48, 52, 56
c. 24, 36, 48, 60, 72, 84, 96, 108, 120
d. 24, 18, 12, 6, 0, -6, -12, -18, -24