In order that a cycle be reversible, following must be satisfied | Thermodynamics

(a) free expansion or friction resisted ex-pansion/compression process should not be encountered
(b) when heat is being absorbed, tempera¬ture of hot source and working sub¬stance should be same
(c) when beat is being rejected, tempera-ture of cold source and working sub-stance should be same
(d) all of the above
(e) none of the above.

Ans: d