Question

if visibility is limited, you should: have your headlights on sound your horn turn on your windshield wipers brake hard

Explanation:

When visibility is limited, having headlights on helps others see your vehicle and allows you to see the road better. Sounding the horn is not the main - action for limited visibility. Turning on windshield wipers is for rain and debris on the windshield, not for general limited visibility. Braking hard can cause accidents if not necessary.

Answer:

Have your headlights on