What is the imminent danger in the following road section?

1. Limited field of vision while overtaking vehicles in front of you.
2. Engine overheating due to the steep climb.
3. Correct answer: The appearance of a vehicle coming from your opposite direction in your driving lane.
4. The crossing of a separation line and inability to return to the roadway’s right.

WhyBeyond the hill crest an oncoming vehicle may suddenly appear in your lane. That is why you keep right.