Consider the reaction
`A(g)+B(g) hArr C(g)+D(g)`
Which occurs in one step. The specific rate constant are `0.25` and `5000` for the forward and reverse reaction, respectively. The equilibrium constant is
A. `2.0xx10^(-4)`
B. `4.0xx10^(2)`
C. `5.0xx10^(-5)`
D. `2.5xx10^(-6)`