"Roly-Poly"

A toy “Roly-Poly” consists of two rigidly attached, hollow, uniform, plastic balls. The upper and lower balls are of radii $6\text{ cm}$ and $9\text{ cm},$ respectively. A small load of mass $250\text{ g}$ is glued at the bottom of the lower ball. This toy has a property that if it is tilted to one side by any angle and then set free, it oscillates and finally settles in the vertical orientation.

Which of the following statements are correct?

A. The greater the mass of the load, the faster the response.

B. The greater the mass of the lower ball, the slower the response.

C. The mass of the upper ball should be less than $150\text{ g},$ and that of the lower ball greater than $150\text{ g}.$

D. The mass of the upper ball should be less than $150\text{ g},$ and that of the lower ball may have any value.

E. The mass of the upper ball should be less than $100\text{ g},$ and that of the lower ball greater than $125\text{ g}.$