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

( A ) $(T_f)_{rev} = (T_f)_{irrev}$
( B ) $(T_f)_{irrev} > (T_f)_{rev}$
( C ) $T_f > T_i$ for reversible process but $T_f = T_i$ for irreversible process
( D ) $T_f = T_i$ for both reversible and irreversible processes$