This is an old question that is no longer in use.
Images may be missing and the information may be dated.
You are driving the car from which the picture is taken. What is the greatest risk facing you?
The motorcycle drivers are by far the biggest risk. The likelihood is very great that they will overtake the cars and therefore require you to keep far right. Many things can happen, for example:
Sure, the distance between the oncoming cars is too short, but this does not entail any direct risk for you.
More examples of explanations: