Plz asap solid geometry word problems

The volume of the sphere is:
 V = (4/3) * (pi) * (r ^ 3)
 Where,
 r: radius of the sphere.
 Sphere A:
 Va = (4/3) * (pi) * (ra ^ 3)
 Va = (4/3) * (pi) * (4 ^ 3)
 Va = (4/3) * (pi) * (64)
 Sphere B:
 Vb = (4/3) * (pi) * (rb ^ 3)
 Vb = (4/3) * (pi) * (3 ^ 3)
 Vb = (4/3) * (pi) * (27)
 The relationship of both volumes is:
 Va / Vb = ((4/3) * (pi) * (64)) / ((4/3) * (pi) * (27))
 Simplifying:
 Va / Vb = 64/27
 
 Va / Vb = 64/27
 option D