The correct option is (a) TB=\((1-\mid\Gamma_s \mid^2) T_p\)
The explanation is: The relation between brightness temperature and the physical body temperature is given by TB=\((1-\mid\Gamma_s \mid^2) T_p\)
Here Γs is the reflection coefficient for a given polarization and emissivity =\(1-\mid\Gamma_s \mid^2.\)