Direct action on Nm Cholinoreceptors is shown by-

Ans. is 'b' i.e.'b' Neostigmine Comparative features of physosdgmine and neostigmine PhysostigmineNeostigmine1. SourceNatural alkaloid form Physosiigma venenosum (Calabar bean)Synthetic2. ChemistryTertiaryr amine derivativeQuaternary' ammonium compound3. Oral absorptionGoodPoor4. CNS actionsPresentAbsent5. Applied to eyePenetrates corneaPoor penetration6. Direct action on Xm cholinoceptorsAbsentPresent7. Prominent effect onAutonomic effectorsSkeletal muscles& Important useMiotic (glaucoma)Myasthenia gravis9. Dose0-5-1 mg oral/parenteral0-I-T0%eye drops0-5-2-5mgi.m./s.c.15-30 mg orally10. Duration of actionSystemic 4-6 hrsIn eye 6 to 24 hrs3-4 hrs.