Final answer:
The major ceremony attended by MLK and his wife Coretta in March 1957 was the Prayer Pilgrimage for Freedom. This event aimed to advocate for civil rights for African Americans and was organized by the NAACP.
Step-by-step explanation:
The major ceremony attended by MLK and his wife Coretta in March 1957 was the Prayer Pilgrimage for Freedom. This event took place on May 17, 1957, and was organized by the National Association for the Advancement of Colored People (NAACP). It was held on the steps of the Lincoln Memorial in Washington, D.C., and aimed to advocate for civil rights for African Americans. The keynote speaker at the event was Dr. Martin Luther King Jr. He delivered a speech calling for an end to racial segregation and discrimination.