Answer:
b. the killing of Trayvon Martin by George Zimmerman
Step-by-step explanation:
The "Black Lives Matter" movement formed by Alicia Garza, Patrisse Cullors, and Opal Tometi developed in response to the killing of Trayvon Martin by George Zimmerman. After the acquittal of George Zimmerman for the killing of Trayvon Martins, the black lives matter movement sprang into a frenzy of online protest with the black live matters hashtags, there has been subsequent protest against the extrajudicial killing of black suspects by police force since its formation.