18. Granulation, or the mottled appearance of the whole solar surface, is an indication of what physical process at work in the sun?

18. Granulation, or the mottled appearance of the whole solar surface, is an indication of what physical process at work in the sun?A)Outflow ofneutrinos from the interiorB) rapid rotaton of the sunC)thermonuclear fusion of hydrgen in the sun's surface layersD)onvective motion of gases in the upper portion of the sun's interior