Short acting anticholinesterase is

(B) Edrophonium# Pyridostigmine:> Resembles neostigmine in all respects but is dose to dose less potent and longer acting, less frequent dosing is required in myasthenia gravis.# Edrophonium:> Resembles neostigmine in action, has a brief duration (10-30 min), suitable as a diagnostic agent for myasthenia gravis and for postoperative decurarization.# Tacrine:> It is a lipophilic acridine compound which interacts with ChE in a manner analogous to edrophonium.> It crosses blood-brain barrier and has a longer duration of action.# Donepezil:> Another centrally acting anti AChE that has produced cognitive and behavioral improvement in AD.> It is long acting and suitable for once daily administration.