Which of the following processes is the entropy change zero?

Which of the following processes is the entropy change zero?

مندرجہ ذیل میں سے کون سا عمل اینٹروپی تبدیلی صفر ہے؟
Explanation

In a reversible adiabatic process, there is no heat transfer (Q = 0).

As a result, the entropy change (ΔS) is zero because entropy change is directly related to heat transfer in a reversible process (ΔS = Q / T).