a) parallel flow
b) cross flow
c) counter flow
d) tangent flow

Answer: b
Explanation: Car radiator and air conditioner evaporator coil uses crossflow heat exchangers. Crossflow heat exchangers are widely used for transfer of heat between a gas and a liquid. In air conditioner evaporator coil, the air flows past the evaporator coils are cooled by the cold refrigerant that is flowing inside the tubes of the coil.