According to the Supreme Court Opinion in Terry V

According to the Supreme Court opinion in Terry v.Ohio,involving a police stop and frisk of a citizen on a street to investigate a possible robbery:

A) in dealing with dangerous situations on city streets,police need an escalating set of flexible responses.
B) police cannot stop citizens without probable cause to believe that crime is afoot.
C) in any instance where the police can stop someone,they can also frisk that person.
D) police cannot stop citizens without clear and convincing evidence that crime is afoot.