$\begin {array} {1 1} (A)\;\large\frac{1}{log_{10}4-log_{10}3} & \quad (B)\;\large\frac{1}{log_{10}4+log_{10}3} \\ (C)\;\large\frac{9}{log_{10}4-log_{10}3} & \quad (D)\;\large\frac{4}{log_{10}4-log_{10}3} \end {array}$