John and Mary are friends who habitually visit each other's apartment unannounced. One-day John decides to visit Mary, finds her not at home, forced his entry through the window and once inside suddenly decides that he could sell Mary's VCR for drug money. John cannot be charged with robbery because he did not enter her apartment by force or fraud, the crucial element needed to satisfy such a charged. What best explains this? a. Actus reus b. Mens rea c. Concurrence d. Causation e. Harm