When is it never acceptable to overtake another vehicle?

Answer: B — When approaching a curve or hill where visibility is limited

Overtaking another vehicle is never acceptable when approaching a curve or hill where visibility is limited because it poses significant safety risks. In these situations, the driver cannot see oncoming traffic, making it difficult to determine whether it is safe to pass. Attempting to overtake can lead to dangerous collisions since the driver may not have enough time or distance to react to any advancing vehicles. It's critical to have clear visibility to ensure that both lanes are clear of vehicles and that there's enough space to maneuver safely. This principle applies universally to all road users to help prevent accidents and promote safer riding practices.