Final answer:
The Prime Time Access Rule was a regulatory measure by the FCC aimed at reducing the monopoly of the Big Three networks over prime-time TV programming to promote diversity and localism.
Step-by-step explanation:
The Prime Time Access Rule was indeed enacted by the FCC, but the question does not specify when this happened. Concerned with the dominance of the Big Three networks (ABC, CBS, and NBC) over what was displayed in prime time television, and their considerable control over the TV industry, the FCC took several steps to promote diversity and localism in programming. The Prime Time Access Rule or PTAR, put into place in 1970, is a notable example of such regulations. It required that one hour of prime time be set aside for local or syndicated programming, limiting the networks' control during that time slot. Though PTAR has since been repealed, it was a significant regulatory decision aimed at reducing network monopoly over prime-time programming and fostering more local content.