What is the thermal conductivity of the wall?

Question

Heat is conduced through a 10 cm thick wall at the rate of 30 W/m2 when the temperature  difference across the wall is 10C. What is the thermal conductivity of the wall?                                  (IES-05)

a. 0.03 W/mK              b. 0.3 W/mK

c. 3.0 W/mK                d. 30.0 W/mk