So we wan't to know the value of 4^3. Lets see what that means. When we have a^n it means we multiply a by itself n times like so: a^1=a, a^2=a*a, a^3=a*a*a, a^4=a*a*a*a. So in our case we have 4^1=4, 4^2=4*4=16 and 4^3=4*4*4=64. So the correct answer is b. 64