Answer:
Particles of the substance are in liquid state will gain kinetic energy between positions C and D.
Step-by-step explanation:
Problem it tells us that between B an C the substance is solid, but I would say that is solid between A and B while between B and C it is a melting process in which particles will gain energy to transform from solid to liquid.
Now between C and D the particles of the liquid will receive energy which is transformed in kinetic energy so the participles will move faster.
Between D and E the particles the energy received is spent by the particles to pass from liquid state to vapors state.