c.

(safest strategy is simply to list out possibilities. It's also helpful to realize that multiples of both 4 and 6 are multiples of 12 (least common multiple btwn the two), so skip over all multiples of 12:)

(4, 8, x12x, 16, 20, x24x, 28, 32, x36x, 40, 44, x48x)

(there total of 8) ;