The United States Did Not Warn the Shah of an Impending

The United States did not warn the shah of an impending revolution (1979) because ________.

A) the U.S. did not view the shah as a friend
B) the shah did not view the U.S. as a friend
C) the U.S. did not know due to the CIA's failure to do their job
D) the U.S. did not know because SAVAK did not pass crucial information to the CIA
E) U.S. diplomats in Iran chose to ignore the information they were gathering