What is necessary for the plain view doctrine to apply?

For the plain view doctrine to apply, it is essential that the officer is lawfully present in a location where they can observe the items in plain view. This means that the officer did not violate the Fourth Amendment by entering a location without proper authority or warrant. The items themselves must be clearly visible, and the officer must be able to recognize them as items that may be subject to seizure based on probable cause. This doctrine allows for the seizure of evidence without a warrant when the officer's observation is made while they are in a position they are legally allowed to be.

The other options do not adequately fulfill the requirements of the plain view doctrine. Prior knowledge of the items is not a necessary condition; lawful presence and observation are the critical factors. Additionally, photographing the items before seizure and having a witness present are not requirements that influence the legality of a seizure under the plain view doctrine. The focus remains on the lawful presence and the items being in plain sight during the observation.