Is it compulsory to file E Return for a PArtnership firm

No....

efilin is compulsory for 44ab and corporate clients only..

thats right.....its optional for others..

It's optional to others

E-Filing is compulsory only for assessee's liable for audit u/s.44AB

efiling is covered under section 139b where u can read that it is not compulsory for the partnership firm who is not to get it's account audited to efile it's return of income.

no