Step 1: Understanding the Concept:
The question asks about the subject matter of the landmark Supreme Court case, \textit{Indian Council of Legal Aid and Advice v. Bar Council of India}. This requires knowledge of important precedents related to the Advocates Act, 1961.
Step 2: Detailed Explanation:
In this case, the Bar Council of India (BCI) had framed a rule that barred individuals who had completed 45 years of age from being enrolled as an advocate. This rule was challenged before the Supreme Court.
The Supreme Court held that the rule was discriminatory, unreasonable, and beyond the rule-making power of the BCI. The Court reasoned that the Advocates Act itself did not prescribe any age limit for enrollment, and the BCI could not introduce such a restriction through its rules as it was not a power conferred upon it by the Act. The Court struck down the rule as ultra vires the Advocates Act.
Therefore, the case directly dealt with the issue of prescribing an age bar on the enrollment of advocates.
Step 3: Final Answer:
The case of \textit{Indian Council of Legal Aid and Advice v. BCI} is the leading authority on the issue that the BCI does not have the power to prescribe a maximum age limit for enrollment as an advocate. Therefore, option (D) is correct.