Correct Answer - D

Applying `(theta_(1)-theta_(2))/t = alpha[(theta_(1)+theta_(2))/2 - (theta_(0))]` two times, we get where alpha is constant.

`(50-45)/5 = alpha[(50+45)/2-(theta_(0))`...............(i)

`(45-41.5)/(5) = alpha[(45+41.5)/2-(theta_(@))]`.......................(ii)

Solving these two equations, we get

`theta_(@)`= temperature of atmosphere = `33.3^(@)`C