On what grounds could a man contest a police search while window-shopping if a robbery was reported in the area?

The correct answer is based on the Fourth Amendment, which protects individuals from unreasonable searches and seizures by law enforcement. This amendment asserts that citizens have a right to privacy in their persons, homes, and possessions, thus requiring law enforcement to have probable cause or a warrant to conduct a search.

In the context of the scenario, while police may have a justification to investigate due to a robbery reported in the area, the individual window-shopping could argue that any search conducted without probable cause specifically related to him or without a warrant constitutes an unreasonable search. Therefore, if he was not personally involved in any suspicious activity and the police had no specific evidence to connect him to the robbery, he could reasonably contest the search on these Fourth Amendment grounds.

The other amendments listed focus on different rights. The Fifth Amendment deals with rights concerning self-incrimination and due process, the First Amendment protects freedom of speech and assembly, and the Sixth Amendment guarantees the right to a fair trial and legal representation. None of these are pertinent in a situation where the legality of a police search is being evaluated.