Answer
a. two adiabatic processes, two isentropic processes.
Work Step by Step
There are adiabatic Compression and Expansion Processes, and there are Iso-Entropic Heat gain and Heat loss.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.