Which of the following options correctly explains the term Heat Budget?

 a) It is the radiation from the earth in the form of long waves
 b) It is the balance between incoming and outgoing radiations
 c) It is the amount of heat which the surface of earth receives from the sun.
 d) It is a mode of transfer of heat through matter by molecular activity

SSC CGL-15

It is the balance between incoming and outgoing radiations. A heat budget is the perfect balance between incoming heat absorbed by earth and outgoing heat escaping it in the form of radiation. If the balance is disturbed, then earth would get progressively warmer or cooler with each passing year.