Frank is an inmate at Greensburg State Prison, and he has just had a contact visit with an old ...

Frank is an inmate at Greensburg State Prison, and he has just had a contact visit with an old friend. Before Frank returns to his cell, prison guards subject Frank to a strip search. Such a search is:
 
  a. constitutional, because prisoners have a diminished expectation of privacy and there is an important government need to maintain prison security.
  b. constitutional, because prisoners forfeit all Fourth Amendment rights.
  c. unconstitutional, unless prison officials have reasonable suspicion to think they will find contraband or other evidence of a crime on Frank.
  d. unconstitutional, unless prison officials have probable cause to think they will find contraband or other evidence of a crime on Frank.