HELP IN 1 MINS ASAP PLEASE

Which rates are unit rates?


Choose all answers that are correct.


A.

200 pages every 2 h


B.

3 water fountains per park

C9m/1s


D90 words/2 mins

Verified Answer :

A, C, and D 
A because for every 2 hours you're reading 200 pages.
C because for every 9 minutes, 1 second? (honestly that confuses me) 
D because for every 2 mins you type 90 words