PLEASE ANSWE

If two charges attract to each other, then which of the following is true?

A. Both charges must be negative.
B. Both charges must be equal in value.
C. Both charges must be positive.
D. Both charges must be different.

Charlie is at an amusement park that has 18 different rides. each ride costs $1.75. the function c(r) = 1.75r represents the total amount of money that charlie will spend if he goes on r rides, but he never goes on the same one more than once. what domain and range are reasonable for the function?