A questions tells me to indicate which of the following are exact numbers and which are measurements?

Question

What's the difference b/w exact numbers and measurements? Here's the rest of the question:

a) mass of a paper clip

b) the surface area of a dime

c) the number of inches in a mile

d) the number of ounces in a pound

e) the mass of 15 ounce can of coffee

I only put four choices. Please answer my first question!

Answer 1

Measurements

a)  b)  e)

Exact

c)  d)