The correct option is A 3 kg
All three masses having same kinetic energy
∵K.E1=K.E2=K.E3
Also we know that kinetic energy is given by, KE=12mv2, where m is mass of the body and v is veocity of the body.
So, m1v21=m2v22=m3v23
It is given that, m1<m2<m3
∴v1>v2>v3
Mass of 3 kg will move fastest among three masses.
Hence option A is the correct answer.
Alternate solution:
Given that kinetic energy of masses is equal,
so KE=12mv2=Constant
so v2∝1m
v∝1√m
If mass is least, velocity is highest.
Mass of 3 kg will move fastest among three masses.
Hence option A is the correct answer.