Under what condition can a person legally ride in or on a trailer or semi-trailer being hauled?

Answer: C — If participating in an approved parade or being transported to/from a worksite

Riding in or on a trailer or semi-trailer can be extremely dangerous and should be avoided unless absolutely necessary. Option A is incorrect because age alone does not make it safe to ride in or on a trailer. Option B is incorrect because it is always dangerous to ride in or on a trailer, regardless of the time of day. Option D is incorrect because safety belts alone are not enough to ensure the safety of riders on a trailer. Option C is the correct answer because participating in a parade or traveling to and from a worksite often requires riding in or on a trailer and is considered a legal and approved exemption. Always prioritize safety and caution when considering riding in or on a trailer or semi-trailer.