Which 2009 US Supreme Court case limited law enforcement's ability to conduct searches incidental to arrest of motor vehicles?

The correct answer, which is the case that limited law enforcement's ability to conduct searches incidental to the arrest of motor vehicles, is not A, but should be identified with another option.

In the context of the question, the case that established limitations on searches of vehicles incident to arrest is "Arizona v. Gant." This ruling holds significant importance because it clarified the scope of the vehicle search exception to the Fourth Amendment's warrant requirement.

In "Arizona v. Gant," the Supreme Court ruled that police may only conduct a warrantless search of a vehicle incident to an arrest when it is reasonable to believe that evidence of the crime of arrest might be found in the vehicle at the time of the search. Moreover, if the arrestee is secured and cannot access the vehicle, officers are typically not allowed to search the vehicle without probable cause.

This ruling aimed to balance law enforcement interests with an individual's right to privacy, thus placing constraints on how police can justify searches of vehicles following an arrest.

For further context, "Horton v. California," "Whren v. US," and "Michigan v. Summers" pertain to different aspects of search and seizure laws but do not specifically address the limitations placed on searches of vehicles incident to arrests