Two conductors have the same resistance at $0^{\circ} C$ but their temperature coefficients of resistance are $\alpha 1 \: and \: \alpha 2$. The temperature coefficient for the parallel combination is

Question

$\begin {array} {1 1} (A)\; \alpha_1 + \alpha_2 & \quad (B)\;\large\frac{(\alpha_1+ \alpha_2)}{2} \\ (C)\;\large\frac{(\alpha_1 \alpha_2)}{(\alpha_1+ \alpha_2)} & \quad (D)\;\large\frac{2(\alpha_1 \alpha_2)}{(\alpha_1+ \alpha_2)} \end {array}$