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

The historical detail that best helps clarify the reader's understanding of the sentence is option B, which states that "gorillas" were hired men who threatened and hurt striking workers. This detail provides context for the mention of workers being harassed on the picket lines. The reference to "gorillas" indicates that there were hired individuals who were responsible for the harassment, suggesting that the workers faced physical intimidation and violence. This detail helps paint a clearer picture of the challenges faced by the workers during the time period in question.