A pendulum clock loses 12s a day if the temperature is `40^@C` and gains 4s a day if the temperature is `20^@C`, The temperature at which the clock will show correct time, and the co-efficient of linear expansion `(alpha)` of the metal of the pendulum shaft are respectively:

Options

A. `60^@C, alpha=1.85xx10^-4//^@C`
B. 30^@C, alpha=1.85xx10^-3//^@C
C. 55^@C, alpha=1.85xx10^-2//^@C
D. 25^@C, alpha=1.85xx10^-5//^@C