The V-T diagram shows process x→y at constant volume (V constant, T increases → P increases), y→z at constant temperature (T constant, V decreases → P increases), and z→x at constant pressure (P constant, V decreases → T decreases).

For an ideal gas, P = nRT/V. Process x→y is isochoric: $P\propto T$. y→z is isothermal: $P\propto \frac{1}{V}$. z→x is isobaric: $V\propto T$.

The correct P-V diagram must show: constant volume line (vertical) for x→y, hyperbolic curve for y→z (isothermal compression), and straight line through origin for z→x (isobaric).

Final Answer: The second option.