Two wires of resistance `R_(1) and R_(2)` at `0^(@)C` have temperature coefficient of resistance `alpha_(1) and alpha_(2)` respectively. These are joined in series. The effective temperature coefficient of resistance is : 

Options

A. `(alpha_(1)+alpha_(2))/(2)`
B. `sqrt(alpha_(1)alpha_(2))`
C. `(alpha_(1)R_(1)+alpha_(2)R_(2))/(R_(1)+R_(2))`
D. `(sqrt(R_(1)R_(2)alpha_(1)alpha_(2)))/(sqrt(R_(1)^(2)+R_(2)^(2)))`

Answer

C