Evaluations for input

<image 1>A transistor, which may be approximated as a hemispherical heat source of radius ro = 0.1 mm, is embedded in a large silicon substrate (k = 125 W/m$\cdot$ K) and dissipates heat at a rate q. All boundaries of the silicon are maintained at an ambient temperature of T$\infty$= 27C,except for the top surface, which is well insulated.evaluate the surface temperature of the heat source for q =4 W.

(A) 340.93K

(B) 350.93K

(C) 360.93K

Answer with the option's letter from the given choices directly. No punctuation.