The correct answer to this open question is the following.
Although there are no options provided, we can say the following.
An officer receives an anonymous tip that controlled substances are being transferred in a particular vehicle to a particular place. This is the only information the officer has on the matter. The best course of action would be for the officer to immediately attempt to corroborate if the tip was true or just a rumor.
This is very important because the police offer cannot act based on rumors, it has to check first the validity of the information, who is providing it. Is he/she a valid source of information? If he/she heard it to the grapevine? Is this a confirmed fact? That is why a key part of the work of the police is the intelligence work, where officers find and collect all the information needed to proceed.