A geometric sequence must have a constant ratio x/y
Now, technically a does, 1, however it's not really a sequence, depending how you define one.
So we need to find one that has a constant multiplier to it. B definitely doesnt as that's just increasing the bottom of the fraction by 1 and to do that you have to multiply by a different number each time.
C however, does, it multiplies by -4 (dont forget that a negative x a negative is a positive), so this is the correct answer.
