A taxi driver that is obliged to wear eyeglasses or any other optical instrument:

1. Must hold an extra pair of eyeglasses or contact lenses at the taxi station.
2. Must ensure that he carries on him a pair of eyeglasses or contact lenses while driving during the night.
3. Must ensure that he carries on him a pair of eyeglasses or contact lenses while driving during the day.
4. Correct answer: Must carry with him an extra pair of eyeglasses or contact lenses while driving.

WhyA taxi driver who must wear glasses or lenses carries a spare pair while driving. Leaving it at the taxi stand is not enough.