During a phase transition of a substance the temperature (T) versus heat energy (Q) graph is shown below. Identify the regions of the graph which show an increase in only kinetic energy.

During the phase transition of a matter there is no change in the kinetic energy of molecules.  But physical state of matter is changed by absorbing or releasing energy. For the same phase with different temperatures kinetic energy of molecules should be different.

$\text{KE}\propto \text{Temperature}$

The below diagram CD, EF shows that there is a change in kinetic energy.