Answers to Test your skill... 

A - Oncoming vehicles, pedestrians, cyclists, farm tractors, a broken down vehicle or a horse rider.

B - Because there is a very restricted view to the left and right in to the major road.

C - Because there is a relatively clear view to the and right into a major road.

D - The motorist from the side the photo was taken.

E - Read down from the top.

F - See Highway Code rule 178. 

G - See Highway Code rule 126.

H - See Highway Code rule 174.

I - See Highway Code rule 129.