You want to double the radius of a rotating solid sphere while keeping its kinetic energy constant. (The mass does not change.) To do this, the final angular velocity of the sphere must be
选项：

A:4 times its initial value.;
B:twice its initial value.;
C:the same as its initial value.;
D:1/2 of its initial value.;
E:1/4 of its initial value.