Water is being boiled in a flat bottomed kettle placed on a stove The area of the bottom is `300cm^(2)` and the thickness is `2mm` If the amount pf steam produced is `1gm min^(-1)` then the difference of the temperature between the inner and the outer surface of the bottom is (thermal conductivity of the matrial of the kettle `0.5calcm^(-1)C^(-1)` latent heat of the steam is equal to `540calg^(-1))` .

A. `12^(@)C`

B. `1.2^(@)C`

C. `0.2^(@)C`

D. `0.012^(@)C`