Two identical particles having the same mass m and charges +q and -q separated by a distance d enter a uniform magnetic field B directed perpendicular to paper inwards with speeds `v_1 and v_2` as shown in Fig. 1.139. The particles will not collide if
A. `dgt m/(Bq) (v_1 + v_2)`
B. `dlt m/(Bq) (v_1 + v_2)`
C. `dgt (2m)/(Bq) (v_1 + v_2)`
D. `v_1 = v_2`