Work, Energy and Power: JEE Main 2025 Physics question

A body of mass '$m$' connected to a massless and unstretchable string goes in verticle circle of radius '$R$' under gravity $g$. The other end of the string is fixed at the center of circle. If velocity at top of circular path is $n\sqrt{gR}$, where, $n \ge 1$, then ratio of kinetic energy of the body at bottom to that at top of the circle is