In torches, search lights and headlights of vehicles the bulb is placed

[B] very near to the focus of the reflector.
Simply understand that, the rays of light passing through the principal focus will go parallel to principal axis after reflection thus, forming a concentrated beam of light. Hence, due to this reason in torches, search lights, and headlights of vehicles, the bulb is placed very near to the focus of the reflector. Your answer should be option [B].