16. When a proton is released from rest in a room, it starts with an initial acceleration a_o toward

16. When a proton is released from rest in a room, it starts with an initial acceleration a_o towards west. When it is projected towards north with a speed v_o it moves with an initial acceleration 3a_o toward west. The electric and magnetic fields in the room are

(a) \frac{ma_o}{e}east, \frac{3ma_o}{ev_o}up
(b) \frac{ma_o}{e}east, \frac{3ma_o}{ev_o}down
(c) \frac{ma_o}{e}west, \frac{2ma_o}{ev_o}up
(d) \frac{ma_o}{e}west, \frac{2ma_o}{ev_o}down