As you drive, you come across a road sign with a telephone symbol. What does this sign indicate?

• It shows that there is a public telephone service available near the road for drivers' use.
  Explanation:

  "This sign shows the presence of a telephone facility on the road."
• It indicates a zone where the use of mobile phones is strictly prohibited while driving.
• It marks a spot designated for emergency phone calls only.
• It warns of upcoming road work involving telephone line repairs.