Is it correct to say five pairs or five pair?

[Limbo]

English Grammar Tests, Elementary Level

ESL/EFL Test #41 "Basic American English", question 2

......... boss said that you work hard.

(a) Your
(b) Yours
(c) You're
(d) You

English Grammar Tests, Elementary Level

ESL/EFL Test #41 "Basic American English", answer 2

Your boss said that you work hard.

Correct answer: (a) Your
_________________________

Is it correct to say five pairs or five pair?

Limbo

[Mister Micawber]

.
Both are OK.
.
_________________
Native English teacher at Mister Micawber's