Answer:
c
Step-by-step explanation:
volume of cylinder = πr^2h
r = 6.5
h = 13+13+13 = 39
cylinder volume = 1647.75π cm^3
volume of one sphere = 4/3 π r^3
= 366.16π cm^3
space not occupied by tennis balls = 1647.75π-3(366.16π)=549.25π cm^3
