12 spheres of the same size are made from melting a solid cylinder of 16 cm diameter and 16 cm height. What is the diameter of each sphere?  Choose the most appropriate option.
A) 4 cm  B) 6 cm  C) 8 cm  D) 10 cm  E) 12 cm

Rationale: "volume of cylinder = pi * r ^ 2 * h volume of a sphere = 4 * pi * r ^ 3 / 3 12 * 4 * pi * r ^ 3 / 3 = pi * r ^ 2 * h r ^ 3 = r ^ 2 * h / 16 = 64 cm ^ 3 r = 4 cm d = 8 cm the answer is c ."
Answer: C