The “Hollywood Ten” were------.
A. Script Writers who were blacklisted in Hollywood for refusing to answer questions posed by the House Un-American Activities Committee
B. Californio beatniks who refused to obey laws against selling and smoking marijuana
C. Actors and actresses who appeared in propaganda films during World War II
D. Movie-studio owners who conspired to run their industry on a system of indentured servitude of the performers.

Hint:- Hollywood Ten, in U.S. history were a total of 10 motion-picture producers, directors, and screenwriters who appeared before the House Un-American Activities Committee in October 1947.
These Ten Hollywood celebrities were as follows:- Edward Dmytryk, Ring Lardner, Jr., John Howard Lawson, Albert Maltz, Samuel Ornitz, Adrian Scott, and Dalton Trumbo, etc.
These were the prominent screenwriters and directors, who became known as the Hollywood Ten, later received jail sentences and were banned from working for the major Hollywood studios as a punishment.

Complete answer:
The Hollywood Ten'' were those Script Writers who were blacklisted in Hollywood for refusing to answer questions posed by the House Un-American Activities Committee. So A is the right answer.
There were 10 Hollywood writers whom no one would hire after they refused to answer the committee's illegal questions.
 And sent to jail and after spending time in prison for contempt of Congress, So they were mostly blacklisted by the several studios of Hollywood.
At least ten members of the Hollywood film industry publicly denounced the tactics employed by the House Un-American Activities Committee (HUAC), an investigative committee of the U.S. in October 1947.

Hence, answer A is the right option.

Note: Apart from this Hollywood writer and scripter, there were also other members of the film industry with alleged communist ties who were later banned from working for the big movie studios.
The Hollywood writers were blacklisted by the communist came to an end in the 1960s.