Under which of the following conditions is it dangerous and unlawful to make a "U" turn?

Making a "U" turn under any of these conditions is considered dangerous and unlawful due to the associated risks and visibility concerns.

When you attempt a "U" turn upon a curve, your view of oncoming traffic is likely obstructed. This lack of visibility increases the chances of a collision, as you may not see vehicles approaching from the opposite direction.

Executing a "U" turn on a hill where there is a clear view of less than 150 meters in either direction brings similar risks. Limited visibility can prevent you from noticing oncoming vehicles or hazards, making a "U" turn in such circumstances hazardous.

Attempting a "U" turn within an intersection is also perilous. Intersections are often bustling with traffic in multiple directions, and making such a maneuver can lead to confusion and accidents as other drivers might not anticipate your movement.

Therefore, all these conditions exacerbate the risks involved with making a "U" turn, illustrating why it is considered unlawful and dangerous in each scenario.