During the 1960s and 1970s, cesar chavez
worked to unionize migrant farm workers by
(1) seizing the land of the lettuce and grape
growers
(2) securing passage of federal legislation to limit
immigration
(3) using nonviolent tactics such as boycotts and
hunger strikes
(4) urging growers to reduce the workforce
through mechanization

The correct answer is option (3) "using nonviolent tactics such as boycotts and hunger strikes".

Explanation:

Cesar Chavez was a leader of American labor and civil right activists that fought to unionized migrant farm workers by the creation of The National Farm Workers Association. Cesar Chaves used nonviolent tactics to support the migrant farm workers. For instance, when Filipino American farm workers protested for higher wages in 1965, he encouraged Americans to boycott table grapes to support them; while he once performed a 24-day hunger strike in 1972 in the Santa Rita Center as a response to Arizona prohibiting boycotts and strikes by farm workers.