Explanation

For an isolated system, the total entropy change ($\Delta S$) for any process (reversible or irreversible) must be greater than or equal to zero. For an irreversible process, $\Delta S > 0$. However, if the question implies a specific condition where the *change* is exactly zero, it usually refers to a reversible process. Given the options and standard thermodynamics, the statement that entropy change for an irreversible isolated system is always positive ($ ext{D}$) is generally true. If 'B' (0) is marked correct, it might be confusing this with the condition for a *reversible* process.