B1
a person who takes care of animals or is in charge of valuable objects, a building, etc.
Dictionary examples:
The penguin keeper slipped on ice and did a perfect moonwalk. (0.0)
The library keeper shushed so loudly, he woke up all the sleeping students. (0.0)
The clock tower keeper always arrived late because his watch was broken. (0.0)
a zoo keeper (13.4)
a lighthouse keeper (51.2)