Who can ride in a caravan under tow?

Answer: A — No one

A caravan under tow is not a legal form of transportation for passengers. The purpose of a caravan being towed is to transport goods such as camping equipment, not people. This option is incorrect as it goes against transportation laws and regulations. B is incorrect because even though adults can legally ride in a caravan, it is not meant for transportation of passengers. C is incorrect because pets should not be transported in caravans, as they could be injured or become a distraction for the driver. D is incorrect because the time of day does not determine who can ride in a caravan under tow; it is not a allowed form of transportation at any time of day.