A cyclic process is shown in the p-T diagram where line AB is passing through the origin. Which of the curves show the same process on a V-T diagram?

We wish to convert P-T graph to V-T graph

Process A to B is isochoric process in which temperature increaes.

Process B-C is isothermal process in which pressure decreases means volume increases.

Hence B-C is isothermal expansion.

Process C to A is isobaric process in which temperature decrease.hence volume decreases.

So C to A is isobaric compression.