Which of the Following Correctly Describes the Difference Between Robbery

Which of the following correctly describes the difference between robbery and extortion?

A) Robbery involves a threat of immediate violence, whereas extortion entails a threat of future violence or other harms.
B) Extortion requires use of force, whereas robbery does not.
C) Modern extortion must be committed by a public official, whereas robbery may be committed by a public or private individual.
D) The crime of extortion requires that the perpetrator act on the threat, whereas robbery may be accomplished by simply placing the victim in fear that a robbery will take place.