A tank has a spherical form with a diameter equal to $3\mathrm{.}2$ m $.$ The tank is used to store iced water. The emissivity of the tank surface is equal to $0\mathrm{.}6$ and the convection coefficient with the outside air at $30C$ is $30\frac{W}{m^{2.}}K.$ The heat is transferred to the tank by convection and radiation. The total heat transfer is $22\mathrm{.}48$ kW and the heat transfer by radiation is $1\mathrm{.}274$ kW $.$ Determine the surface temperature of the tank.

a$.,275\mathrm{.}87K$

b$.294\mathrm{.}5$ K

c$.,281\mathrm{.}02K$