Peaches are being sold for $2 per pound. if x represents the number of pounds of peaches bought and y represents the total cost of the peaches, which best describes the values of x and y?
a: the values of both x and y can be any real number.
b: the values of both x and y will be real numbers greater than or equal to 0.
c: the value of x can be any real number, but the value of y will always be a real number greater than or equal to 0.
d: the value of x can be any real number greater than or equal to 0, but the value of y must be an integer greater than or equal to 0.