A charged particle moving along +ve x-direction with a velocity v enters a region where there is a uniform magnetic field `B_0(-hat k), from x=0 to x=d.` The particle gets deflected at an angle `theta` from its initial path. The specific charge of the particle is
A. `(v cos theta)/(Bd)`
B. `(v tan theta)/(Bd)`
C. `v/(Bd)`
D. `(v sin theta)/(Bd)`