Why is it not the safest choice to pass a school bus with flashing amber lights?

• The bus is reducing its speed.
• The bus may be stopping.
• Both A and B
  Explanation:

  "It is not safe to pass a school bus with flashing amber lights, as this indicates it is slowing down and may be stopping to allow passengers on or off. If you must proceed, do so with extreme caution."
• None of the above.