Answer:
b. 4
Step-by-step explanation:
So, here we have an exponential function.
Remember that an exponential function has the form:

Where a represents an initial amount, and r is the rate of this amount to change. (Increase, or decrease).
So, given that the population of City A in 2000 was 40 thousand people and the population increased by 13% each year, we can say that

So,

For city B:

But something different happens with city C. This is not an exponential function, this is a linear function.
So,

Cindy: 4mph
Taylin: 4m/30 min : 8 mph
Judy:5.5m/45min : 7mph
I hope this helps you
4.4-7,8
16-7,8
8,2