Greg Deveroux was walking home from a friend's house when three individuals stopped him as he crossed through a park. He was physically attacked, and his wallet containing cash and credit cards was stolen after one of the attackers pressed a knife against his ribs. Fortunately, Greg escaped without injury and was able to report the crime to police when he returned home. Which of the following crimes were committed? Select all that apply.
a) robbery
b) burglary
c) identity theft
d) aggravated assault