How is the equilibrium constant for the forward reaction of an equilibrium (K_f) related to that of the reverse reaction (K_r)?

• A.(K_r) is the additive inverse of (K_f)
• B.(K_r) is the multiplicative inverse of (Kf)
• C.(K_r) is the same as (K_f)
• D.the product of (K_r) and (K_f) is zero