A parallel plate condenser is filled with two dielectrics as shown. Area of each plate is \[A{{m}^{2}}\]and the separation is t m. The dielectric constants are \[{{k}_{1}}\] and \[{{k}_{2}}\] respectively. Its capacitance in farad will be

• A. \[\frac{{{\varepsilon }_{0}}A}{t}\left( {{k}_{1}}+{{k}_{2}} \right)\]
• B. \[\frac{{{\varepsilon }_{0}}A}{t}.\frac{{{k}_{1}}+{{k}_{2}}}{2}\]
• C. \[\frac{2{{\varepsilon }_{0}}A}{t}\left( {{k}_{1}}+{{k}_{2}} \right)\]
• D. \[\frac{{{\varepsilon }_{0}}A}{t}.\frac{{{k}_{1}}-{{k}_{2}}}{2}\]