Atropine and acetylcholine show the following type ofantagonism-

Ans. is 'a' Le., Competetive [Ref: K D Tripathi 7th/ e p. 59}Competitive (equilibrium type)Noncompetitive1) Antagonist binds with the same receptor as the agonist2) Antagonist resembles chemically with the agonist3) Parallel nghtward shift of agonist DRC4) The same maximal response can be (surmountable antagonism)Binds to another site of receptorDoes not resembleFlattening of agonist DRCMaximal response is suppressed (unsrmountable antagonism)5) Intensity of response depends on the concentration of both agonist and antagonistMaximal response depends only on the concentration antagonist6) Exampies ACr - atropine Morphine-NaioroneDiazepam-Bicuclline