The sentence correctly joins these simple sentences is A.Cesar Chavez, whom was once a migrant farmer, worked to help migrant workers.
What possessed Cesar Chavez notoriety?
American labor organizer and leader Cesar Chavez was also a civil rights fighter.
He co-founded the National Farm Workers Association with Dolores Huerta, which combined with the Agricultural Workers Organizing Committee to form the labor organization United Farm Workers.
Cesar Chavez, a great American hero, was an advocate of militant nonviolent social change, a leader in the fields of civil rights, Latino and farm labor, as well as the environment and consumer rights.