To solve this problem we will first find the Mass of the Object given by Newton's second law and then apply the Kinetic Energy Theorem.
According to Newton's second law we have to
Where,
F = Force
m = mass
a = Acceleration, at this case is the same gravitational acceleration ()
Therefore the mass of the object is
The cinematic energy theorem tells us that
Where,
m = mass
v = Velocity
Replacing
Therefore the correct answer is B.