Which of the following is true about vehicle maintenance?

• Never mix different types of tires (radial with bias-belted)
• Check tire pressure when the tire is cold for an accurate reading
• Regular maintenance of mirrors, mufflers, horn, and wipers is essential
• All of the above
  Explanation:

  "To ensure passenger safety and comply with the law, you must: 1. Never mix different types of tires (radial with bias-belted). 2. Check tire pressure while the tires are cold for accuracy. 3. Regularly maintain mirrors, mufflers, horn, and wipers."