The state of a mole of an ideal gas changed from state `A` at pressure `2P` and volume `V` follows four different processes and finally returns to initial state `A` reversibly as shown below in the graph. By interpreting the graph, answer the following questions.

In state `D` to state `A`, what kind of process is followed?

Options

A. Isobaric expansion
B. Isobaric compression
C. Isochoric process
D. Isothermal compression

Explanation

Expansion from state `D` to state `A` occurs at constant volume (isochoric process) `=V`