A proton released from rest starts with acceleration $a_0$ towards west. When projected towards north with speed $v_0$, it moves with initial acceleration $3a_0$ towards west. The electric and magnetic fields in the room are:

1. A
   $\frac{m{a}_0}{e}$ west, $\frac{2m{a}_0}{e{v}_0}$ up
2. B
   $\frac{m{a}_0}{e}$ west, $\frac{2m{a}_0}{e{v}_0}$ down
3. C
   $\frac{m{a}_0}{e}$ east, $\frac{3m{a}_0}{e{v}_0}$ up
4. D
   $\frac{m{a}_0}{e}$ east, $\frac{3m{a}_0}{e{v}_0}$ down