Recall the relationship between the equilibrium constant for a forward reaction and that for a reverse reaction. The equilibrium constant for the reverse reaction is the of the equilibrium constant for the forward reaction.

Reciprocal

Explanation:

To buttress the point we are driving at, let’s consider the following hypothetical chemical reaction.

A + B <——-> C + D

In the forward reaction, we can calculate the equilibrium constant as the following. Let’s represent this by Kf

Kf = [C][D]/[A][B]

For the backward reaction, that is A+B as reactant, giving C+D as product. Let’s represent the equilibrium constant for the backward reaction as Kb

Kb = [A][B]/[C][D]

What we see here is that if we multiply the values of the equilibrium constant for the forward reaction by the value of the equilibrium constant for the backward reaction, we get a value of 1. Hence, we can conclude that the value of the chemical equilibrium for the forward reaction is a reciprocal of the value of the chemical equilibrium for the backward reaction.

i think it's letter a.