Choose the correct statements.

a. The Kelvin Statement of the Second Law of Thermodynamics says that no process is possible whose sole result is the conversion of heat into work.

b. A consequence of the Kelvin Statement of the Second Law of Thermodynamics is that a heat engine cannot convert all of the heat transferred from the hot reservoir into work.

c. A consequence of the Kelvin Statement of the Second Law of Thermodynamics is that heat removed from a hot reservoir cannot be used to do work.

d. A consequence of the Kelvin Statement of the Second Law of Thermodynamics is that a heat engine does not have to expel some heat energy into a cold reservoir.