A deuteron and an $\alpha$ - particle are placed in an electric field. The forces acting on them are F₁ and F₂ and their accelerations are a₁ and a₂ respectively

(i) $F_1=F_2$           

(ii) $F_1\ne F_2$

(iii) $a_1=a_2$          

(iv) $a_1\ne a_2$