The correct answer is A) Searching a person’s house without a warrant
The case Mapp v. Ohio is about Dollree Mapp, a woman that was convicted of possessing obscene materials after the police searched her house illegally looking for a fugitive.
The case was decided by 6-3 in favor of Dollree Mapp. In the opinion of the Supreme Court evidence that is obtained by searches and seizures that violate the 4th Amendment are inadmissible in states courts.
If this evidence is admitted in a case, it would encourage the disobedience of the Federal Constitution because then it would not be needed any legal warrant.