Figure shows the  P-V diagram for a fixed mass of an ideal gas undergoing cyclic process  ABCA. AB  represents isothermal process. Which of the graphs shown in figure represents the P-T diagram of the cyclic process?

Process AB must be a downward vertical straight line as temperature is not changing and pressure is decreasing in the process. Then process BC is an isobaric process so here it must be a horizontal straight line and finally process CA is an isochoric process when volume remain constant so on P-T curve this will be a straight line passing through origin.