Is 'school' a collective noun, proper noun, or common noun?

Question

In case when we refereed school as an Collective Noun then what about class ( group of students)

In case when it is used as an Proper Noun but only when both the speakers know about which school we are talking because then only we can say it a Proper Noun

In another case when it is refereed as an Common Noun like any school

I am pretty much confuse whether it is a Proper Or Collective Or Common Noun.

Answer 1

"There is a school near my home" = common noun.

"He is a teacher at Newtown School" = proper noun (not because both speakers know the school, but because it is the school's official name).

School in a different sense (a school of porpoises) is a collective noun.