Question

if the police arrive at Larry's office without probable cause or a warrant and demand to search the premises which amendment protection from this type of search

Answer 1

the 4th amendment protects us

Answer 2

The amendment that offers protection against this type of search is THE FOURTH AMENDMENT.
The fourth amendment provides that each man's home is his own castle and is protected from unlawful charges unless there is a probable cause and in this case a search warrant must be created before the search can be carried out by the law enforcement agents.