What significant event happened in memphis tennessee in april 1968? the cuban missile crisis was over. john f. kennedy was assassinated. malcolm x was assassinated. martin luther king jr. was assassinated.

Correct  Martin Luther King, Jr., was assassinated.

Details:

Dr. Martin Luther King, Jr., was assassinated on April 4, 1968, at the Lorraine Motel in Memphis, Tennessee.  He was one of America's greatest civil rights leaders.

Another civil rights activist, Malcolm X, was assassinated on February 21, 1965, at the Audubon Ballroom in Manhattan, New York.

President John F. Kennedy was assassinated on November 22, 1963, in Dallas TX.

The Cuban Missile Crisis was a 13-day confrontation over nuclear weapons that the USSR placed in Cuba.  The crisis could have led to war, but that was averted.  The standoff ended October 28, 1962.

Martin Luther King Jr. was assassinated.

Explanation:

The correct answer on odyssey is D "Martin Luther King Jr. was assassinated."