In a K9 scan, which of the following is true?

A positive K9 scan provides law enforcement with probable cause to conduct a search of the vehicle. However, this does not necessarily extend to searching every person in the vehicle. While a K9's alert might justify a search of the vehicle itself, it does not automatically allow for the searching of all individuals inside, especially if those individuals are not voluntarily consenting to a search or do not possess any reasonable suspicion of wrongdoing.

A positive scan indicates that the dog detected the presence of a substance that may indicate illegal activity, which grants officers the right to investigate further, but they must still adhere to the legal standards regarding individual searches. This means that usually they can only search individuals if they have specific cause related to those individuals or if they are the owner of the vehicle, which aligns with the principles governing search and seizure.

In this case, stating that only the driver or owner of the vehicle can be searched aligns with these legal principles, making it the accurate answer. The other choices pertain to misconceptions about procedures following a K9 alert or misinterpretations of individual rights in the context of vehicle searches.