Answer:
B. The amount spent on grapes compared with the weight of the purchase.
Explanation:
A: The shoe size of a young girl compared with her age in years. For the first few years of a girl's life, her shoe size is relatively the same. When she goes through a growth spurt, her shoe size increases exponentially. So, that is not a constant rate of change.
B: The amount spent on grapes compared with the weight of the purchase. In most grocery stores, grapes are sold based on their weight, like $2.50 per pound. With each increase in 1 pound, the cost increases by $2.50. That is a constant rate of change.
C: The number of people on a city bus compared with the time of day. This value widely changes throughout the day. For example, during rush hour, there will be many people. But during times at, say, 2 to 3 AM, there will not be many people. So, this is not a constant rate of change.
D: The number of slices in a pizza compared with the time it takes to deliver it. The number of slices in a pizza never changes, so it does not depend on the time it takes to deliver. There is no rate of change.
So, B is your answer.
Hope this helps!