A parallel plate capacitor is of area 6 cm2 and a separation 3 mm. The gap is filled with three dielectric materials of equal thickness (see figure) with dielectric constants K1 = 10, K2 = 12 and K3 = 14. The dielectric constant of a material which give same capacitance when fully inserted in the above capacitor, would be

• A. 4
• B. 36
• C. 12
• D. 14