P-V Diagrams & Cyclic Processes question from MHT CET 2024 (11 May, Shift 2)

Answer: (d)

1. AB isothermal: $T$ constant while $P$ falls, so AB is a vertical line on the P-T graph.
2. BC isobaric: $P$ constant, so BC is a horizontal line.
3. CA adiabatic: $P \propto T^{\gamma/(\gamma-1)}$, a rising curve (not a straight line), which rules out the straight-line triangles (G) and (H).
4. (F) puts C on the constant-$T$ line through A, which is wrong; (E) has AB at constant $T$, BC at constant $P$ and a curved CA.
5. So the answer is (d) (E).