JEE Main Physics question

An object of mass m is attached to a light string which passes through a hollow tube. The object is set into rotation in a horizontal circle of radius r₁. If the string is pulled, shortening the radius to r₂, the ratio of the new kinetic energy to the original kinetic energy is

• (A)(r₂/r₁)²
• (B)(r₁/r₂)²Correct
• (C)r₁/r₂
• (D)r₂/r₁