When are you allowed to park on the street with double yellow lines?

Answer: C — Never, unless there are exceptions indicated

Double yellow lines are a clear indication that parking is not permitted at any time. This rule is in place to ensure the safety and accessibility of the roads, as parking in these areas can obstruct traffic flow and create hazards for other road users. Exceptions typically include specific signage that might allow for certain types of parking, such as loading or unloading for a limited time, but these would be explicitly indicated. Therefore, the correct understanding is that under usual circumstances, unless specific exceptions are posted, parking is strictly prohibited at all times on roads marked with double yellow lines.