Two blocks A and B of masses m and 2m placed on a smooth surface are travelling in opposite directions with velocities of 6 m/s and 4 m/s respectively. A perfectly elastic spring is attached to block A. If after collision, velocity of A is \[\frac{2}{3}\,\,m/s\] towards right , then velocity of block B would be

• A. \[\frac{4}{3}\,m/s\] towards left
• B. \[\frac{16}{3}\,m/s\] towards left
• C. \[\frac{28}{3}\,m/s\] m/s towards left
• D. 4 m/s towards left