An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system If $T_i$ is the initial temperature and $T_f$ is the final temperature, which of the following statements is correct?

Question

$\begin {array} {1 1} (A)\;(T_f )_{irrev}>(T_f )_{rev} & \quad (B)\;\text{ $T_f > T_i$ for reversible process but $ T_f = T_i$ for irreversible process.} \\ (C)\;(T_f )_{rev} = (T_f)_{irrev} & \quad (D)\;\text{ $T_f =T_i$ for both reversible and irreversible processes.} \end {array}$