Should be 'standing on the pulpit' (or 'a pulpit')
Why not "anasimama" ?
"kusimama" is a process verb (not covered yet on duolingo, as far as I can see). "anasimama" means: he is standing up, he is stopping (if he was in motion before), amesimama means: he has stood up = now he stands.
Why not "he has stood on the pulpit"?
Should be 'standing IN THE pulpit'
Yes, at least the kind we find in a church.