A unit mass of a substance undergoes an irreversible process from state 1 to state 2 while gaining heat from the surroundings at temperature T in the amount of q. If the entropy of the substance is s1 at state 1 and s2 at state 2, the entropy change of the substance Δs during this process is (a) Δs < s2 – s1 (b) Δs > s2 – s1 (c) Δs = s2 – s1 (d) Δs = s2 – s1 + q/T (e) Δs > s2 – s1 + q/T