A particle of positive charge q and mass m enters with velocity `Vhati` at the origin in a magnetic field `B(-hatk)` which is present in the whole space. The charge makes a perfectely inelastic collision with an identical particle (having same charge) ar rest but free to move at its maximum positive y-coordinate. After collision, the combined charge will move on trajectory where `r=(mV)/(qB)`.
A. `y=(mv)/(qB)x`
B. `(x+r)^2+(y-r//2)^2=r^2//4`
C. `(x+r)^2+(y-r//2)^2=r^2//8`
D. `(x-r)^2+(y+r//2)^2=r^2//4`