Answer:
B. Typing 35 words per minute.
A unit rate is x per 1.
Basically, unit rate is something per 1 unit of whatever it is.
75/5 = 15. Therefore, 15 miles per 1 gallon would be the unit rate for A.
8/3 = 2.67, so the unit rate for C would roughly be $2.67 for 1 bottle of soda. And so on and so forth.