To overtake in a **tunnel**, it is important to consider the road conditions. The regulations allow overtaking in tunnels **only if there is more than one lane for each direction of travel**. This is because, under these conditions, it is not necessary to invade the opposite lane, which reduces the risk of accidents.

- **Overtaking in tunnels**: It is prohibited to overtake in tunnels when there is only one lane per direction, as this would involve invading the opposite lane, increasing the risk of head-on collisions.

- **Conditions for overtaking**: In general, overtaking must be done safely, ensuring good visibility and enough space to maneuver without endangering other road users.

Therefore, the correct answer is that you can overtake in a tunnel, but only if there is more than one lane for each direction of travel, thus ensuring the safety of all drivers.