Leonard is a heroin addict. he is very careful about overdosing. he typically shoots up in his basement apartment, but is now at a friend's house and needs a fix really badly. he's never done drugs at his friend's house before, but he's desperate. he injects his normal "safe" dosage of heroin but almost dies of an overdose. according to the principles of classical conditioning, what happened? a. leonard's friend switched his drugs in order to teach him not to use drugs by switching his us with his cs. b. leonard took his dose too soon and his body already had too much. c. the effect of the heroin was increased because leonard injected it in a strange environment and his body could not use the stimuli in his basement to prepare for it. d. leonard's drug tolerance had reached its limits thus his us was confounded with his cs and ur.