Which of these BEST describes the My Lai Incident in early 1968?

Responses
A a massacre of unarmed Vietnamese villagers by US troopsa massacre of unarmed Vietnamese villagers by US troops
B a controversial moment at the Woodstock concert in New Yorka controversial moment at the Woodstock concert in New York
C an anti-war protest on an American college campus that turned violentan anti-war protest on an American college campus that turned violent
D a race riot that occurred during the "Freedom Rides" in Mississippi in 1961.

A a massacre of unarmed Vietnamese villagers by US troops