Which of the following represent sterling cycle

Correct option is C

​$$\begin{aligned}&\textbf{Stirling Cycle Characteristics:} \\[1em]&1. \ \textbf{Processes:} \\&\quad \circ\ 1 \rightarrow 2: \text{ Isothermal compression (heat rejection at } T_C\text{)} \\&\quad \circ\ 2 \rightarrow 3: \text{ Isochoric heat addition (regeneration)} \\&\quad \circ\ 3 \rightarrow 4: \text{ Isothermal expansion (heat addition at } T_H\text{)} \\&\quad \circ\ 4 \rightarrow 1: \text{ Isochoric heat rejection (regeneration)} \\[1em]&2. \ \textbf{Key Features in Diagrams:} \\&\quad \circ\ \textbf{P-V Diagram:} \text{ Two isotherms (curved) + two isochores (vertical)} \\&\quad \circ\ \textbf{T-S Diagram:} \text{ Two isotherms (horizontal) + two isochores (vertical)}\end{aligned}$$​​