Correct Answer - A

Let `theta` be the temperature of junction.

`H_(1),H_(2),H_(3)` and `H_(4)` be the heat currents. Then and

`H_(1)=H_(2)+H_(3)+H_(4)`

or `(100-theta)/R=(theta-50)/R+(theta-50)/R+(theta-0)/R`

(R = Thermal resistance of each part of two rods)

Solving these two equations, we get

`theta= 50^(@)`C