Respuesta :

The answer is c. 

(a)

x * 2 = y
2 * 2 = 4 
3 * 2 = 6
4 * 2 = 8 not 9

(b)

unknown formula

(c)

x * 3 = y
4 * 3 = 12 
5 * 3 = 15
6 * 3 = 18

(d)

x * 4
1 * 4 = 4
2 * 4 = 8
3 * 3 = 9 not 15