When driving in fog, you should use:

Low beams.. Section 2.12: Use low beam headlights and fog lights for best visibility.

When driving in fog, you should use:

ANSWER BREAKDOWN
  • A. Incorrect. "High beams." is not correct. Use low beam headlights and fog lights for best visibility.
  • B. Correct. Use low beam headlights and fog lights for best visibility.
  • C. Incorrect. "Parking lights only." is not correct. Use low beam headlights and fog lights for best visibility.
  • D. Incorrect. "No lights." is not correct. Use low beam headlights and fog lights for best visibility.