Two identical rods are made of different materials whose thermal conductivities are `K_(1) and K_(2)`. They are placed end to end between two heat reservoirs at temperatures `theta_(1) and theta_(2)`. The temperature of the junction of the rod is
A. `(theta_(1) + theta_(2))/2`
B. `(K_(1)theta_(1) + K_(2) theta_(2))/ (K_(1) + K_(2)`
C. `(K_(1)theta_(2) + K_(2)theta_(1))/(K_(1) + K_(2))`
D. `(K_(1)theta_(1)+ K_(2)theta_(2))/([K_(1)-K_(2)])`