Answer:
A
Step-by-step explanation:
"The case of actress Jean Muir marked the first and most famous indication of Counterattack’s influence. In August 1950, only weeks after the publication of Red Channels, Theodore Kirkpatrick of American Business Consultants discovered that Muir was scheduled on August 27 to appear on the NBC-TV sitcom The Aldrich Family, despite her sizeable entry in Red Channels."