D is a function because there are no repeated x values
for example b is not a function because we have (0,-7) and (0,-9)
3(25x^3-16)
Hope that is what you were looking for
It would be to little because it would only be 30 cents
C=d x pi
d= 24
C= 24 x 3.14
C=75.36 inches
hope this helps
