What did studios compile as a response to HUAC's investigations?

Studios compiled a blacklist of individuals, including writers, directors, and actors, who were deemed to have communist affiliations or sympathies as a direct response to the House Un-American Activities Committee (HUAC) investigations. This action stemmed from the climate of fear and suspicion during the early Cold War period, where accusations of communism could result in significant professional and personal consequences. The blacklist served as a means for studios to distance themselves from controversy and to protect their financial interests, leading to the systematic exclusion of these individuals from work in Hollywood.

The other options reflect different aspects of the political climate during this period but do not accurately capture the primary response by the studios. For instance, while some studios may have created reports or lists regarding political affiliations, the most notable and historically significant response was the creation of the blacklist. The focus on political themes in film was also impacted by these investigations, but the direct actions taken were primarily concerned with maintaining a barrier against suspected communists, solidifying the blacklist's central role in this turbulent period of filmmaking history.