Final answer:
The exception to the warrant requirement for a probable cause search of a motor vehicle in a public area is the automobile exception, which allows police to search a vehicle without a warrant if they have probable cause to believe it contains evidence of a crime. The correct option is (3)
Step-by-step explanation:
The exception to the warrant requirement for a probable cause search of a motor vehicle in a public area is the automobile exception. The Fourth Amendment protects individuals from unreasonable searches and seizures and typically requires law enforcement to obtain a warrant based on probable cause. However, due to the inherent mobility of vehicles and the lower expectation of privacy in automobiles compared to homes, the Supreme Court has carved out the automobile exception. Under this exception, if police have probable cause to believe that a vehicle contains evidence of a crime, contraband, or illegal substances, they can search the vehicle without a warrant.
It's important to note that the other options given—plain view doctrine, inventory search exception, and exigent circumstances—are also exceptions to the warrant requirement, but they are not specifically tailored to automobile searches the way the automobile exception is. The plain view doctrine allows officers to seize evidence without a warrant if it is clearly visible, the inventory search exception applies when the police tow and inventory a car after an arrest, and exigent circumstances apply when there is a pressing need to act and no time to get a warrant.