The caretaker of a public building

Answer: Option C

One word substitute is Custodian.

Dean: the head of the chapter of a cathedral or collegiate church.
Curator: a keeper or custodian of a museum or other collection.
Custodian: a person who has responsibility for taking care of or protecting something.
Warden: a person responsible for the supervision of a particular place or activity or for enforcing the regulations associated with it.