your answer is B, 3. to divide exponents with the same base, you subtract them:
7ˣ ÷ 7⁵ = 7⁻² ... basically, what you have to do here is choose an x-value for your exponent that will result in -2 when you subtract (x - 5 = -2 is the expression you could use to represent it).
3 minus 5 gives you -2, so you can see that your exponent needs to be 3 for the equation to be true.
