To drive in **heavy fog**, it is important to use the appropriate lights to improve visibility and safety. In this case, the correct combination is to use the **fog lights along with the dipped beam headlights**.

- **Fog lights**: These lights are specifically designed for low visibility conditions, such as fog. They can be used together with the dipped beam headlights to improve road visibility and make the vehicle more visible to other drivers.

- **Dipped beam headlights**: Also known as low beam headlights, they are suitable for low visibility conditions and can be used together with the fog lights to provide adequate illumination without dazzling other drivers.

Using only the position lights (as in answer 2) is not sufficient in foggy conditions, as they do not provide the necessary illumination to see and be seen. Additionally, the hazard lights (mentioned in answer 3) are not designed to improve visibility in fog, but rather to warn of a stop or emergency. Therefore, the combination of **fog lights and dipped beam headlights** is the correct option for driving safely in dense fog conditions.