The correct answer is A) the United States supported Iraq in a war with Iran.
The other options of the question were B) the Unites States did not sanction Israel for invading Lebanon. C) the United States had backed an unpopular leader in Iran. D) the United States had tried to destroy the PLO.
A US marine barracks in Beirut were targeted by terrorists in 1983 because the United States supported Iraq in a war with Iran.
We are talking about the 1983 incident in Beirut, Lebanon, where a s*icide bomber crashed into the barracks of the American marines on October 23, 1983. This terrorist act was no the only one in Beirut. On the same day, something similar happened in the French barracks. These incidents made President Ronald Reagan ordered the removal of US troops from Lebanon in February 1984.