Why Were Yippie Leader Abby Hoffman and President Carter's Daughter

Why were Yippie leader Abby Hoffman and President Carter's daughter Amy acquitted of trespass even though they admitted occupying several buildings at the University of Massachusetts?

A) President Carter intervened and pressured the judge to issue a directed verdict.
B) The prosecution made a serious procedural error.
C) They argued that although they acted illegally, their actions were justified to prevent more dangerous crimes by the CIA ( the defense of "necessity") .
D) To avoid embarrassing the administration, the Secret Service suppressed evidence that most likely would have led to conviction.