What does this sign mean?

• A. Road under repair, slow down.
• B. Steep down-grade in the road ahead, slow down.
  Explanation:

  "There is a steep hill ahead. You should slow down and change down one or two gears to allow your engine to take over some of the braking. Be careful you don't suffer from 'brake fade' where your brakes stop being effective. If you notice this happening, pull over immediately and let the brakes cool down."
• C. Road ahead slippery when wet, drive carefully.