Correct option is (c) \(\frac{[B_t]}{[A_t]}\)

The explanation: The biphasic system is represented by the following reaction

Kw and Korg represents equilibrium constants for water and organic phase respectively. PA and PB are partition co-efficients of A and B respectively.

Kbiphasic represents the apparent equilibrium constant and is given by, \(\frac{[B_t]}{[A_t]}\),

Where At = Concentration of A in total solution and Bt = Concentration of B in total solution.