An object is rolling without slipping, with a translational kinetic energy of $K E_{\text {trans and a }}$ rotational kinetic energy of $K E_{\text {rot. }}$ If $K E_{\text {trans }} / K E_{\text {rot }}=3 / 2,$ what might this object be,
a. a hoop,
b. a spherical shell,
c. a solid cylinder, or
d. a solid sphere?