Which of the following is not an example of biased or discriminatory language?
a. the policemen of this city are underpaid.
b. there are lots of girls who work as firefighters or police officers.
c. would someone call a firefighter?
d. a firefighter must always remember his personal breathing apparatus.

A.The policemen of this city are underpaid. Should be in gender neutral (police officers)

B.There are lots of girls who work as firefighters or police officers. (noun girls is emphasized which gives this sentence a negative connotation)

C. Would someone please call a firefighter? (correct answer)

D. A firefighter must always remember his personal breathing apparatus (pronoun his used instead of its)

The answer is most likely d