Cesar Chavez worked to help migrant farmers. He was once a migrant farmer.
Which sentence correctly joins these simple sentences?
A.
Cesar Chavez, whom was once a migrant farmer, worked to help migrant workers.
B.
Cesar Chavez who was once a migrant farmer worked to help migrant workers.
C.
Cesar Chavez, was once a migrant farmer, worked to help migrant workers.
D.
Cesar Chavez, who was once a migrant farmer, worked to help migrant workers.