A particle is moving in a straight line and passes through a point \[O\] with a velocity of 6 \[m{{s}^{-1}}\] .The particle moves with a constant retardation of 2 \[m{{s}^{-2}}\] for 4 s and there after moves with constant velocity. How long after leaving \[O\] does the particle return to \[o\]?

• A. 3 s                   
• B. 8 s
• C. Never   
• D. 4 s