When energy is added to a substance at constant volume and pressure, its temperature increases except .
A. when the substance is in it gaseous state
B. when the substance is undergoing a phase change
C. when it has reached its specific heat capacity
D. when its molecules are gaining kinetic energy

A. When the substance is in its gaseous state.

Explanation:

When a substance is expanding against its constant volume and pressure, its temperature increases except when the substance is in gaseous state and not in liquid or solid state. So the internal energy increase in the system not only increases and maintaining the volume and pressure of the system remains constant in its gaseous phase. In the first law of Thermodynamics, it is used specifically that to especially in the case of gaseous system.