Read the excerpt from We Shall Not Be Moved. Publicity was another vital need — photos and eyewitness accounts of workers on the picket lines being harassed by gorillas and police. The picket lines themselves would have to be organized.

Which historical detail best helps clarify a reader’s understanding of the sentence?

Unions at the time were dominated by men.
“Gorillas” were hired men who threatened and hurt striking workers.
“Shirtwaists” are what people call “blouses” today.
Women’s clothing first began to be mass produced in the early twentieth century.