Final answer:
The rule that states a fiduciary of a plan under ERISA must act prudently is known as the Prudent Person Rule. This rule requires fiduciaries to invest with the same care and diligence as a reasonably knowledgeable and prudent investor would under similar circumstances.
Step-by-step explanation:
The rule that governs the fiduciary responsibilities of a plan covered by the U.S. Employee Retirement Income Security Act (ERISA) is the Prudent Person Rule. The Prudent Person Rule states that a fiduciary should act with the care, skill, prudence, and diligence under the circumstances then prevailing that a prudent man acting in a like capacity and familiar with such matters would use in the conduct of an enterprise of a like character and with like aims. Therefore, the answer to the question is option b) Prudent Person Rule.
Pension insurance and the Pension Benefit Guarantee Corporation, along with other safety nets such as Deposit insurance through the Federal Deposit Insurance Corporation and Workman's compensation insurance, are part of a broader context to protect employees and their finances. Within this framework, as compared to traditional pension plans, defined contribution plans such as 401(k)s and 403(b)s have become more prevalent, where both employee and employer contribute funds to the employee's retirement account.