'police officer' vs 'police man'

[Wiola]

English Error, Elementary Level

ESL/EFL Test #18 "Cat and mouse", question 7

He then took the jar to a police station and hoped that possibly one of the police agents could help.

(a) took
(b) possibly
(c) agents

English Error, Elementary Level

ESL/EFL Test #18 "Cat and mouse", answer 7

He then took the jar to a police station and hoped that possibly one of the police officers could help.

Correct entry: officers
The error was: (c) agents

You have found the error but your entry is incorrect.
He then took the jar to a police station and hoped that possibly one of the police man could help.
_________________________

what's wrong with police man?

Wiola

[Mister Micawber]

.
Two things are wrong. First, policeman is a single word, and second, the sentence requires the plural: one of the policemen.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mister Micawber