Final Answer:
Association v. Loeb case addressed the issue of a. Unauthorized practice of law by nonattorneys engaged in tax practice.
Step-by-step explanation:
The Lowell Bar Association v. Loeb case specifically addressed the issue of the unauthorized practice of law by nonattorneys engaged in tax practice. This legal case focused on the boundaries and regulations concerning who can engage in legal practice, particularly in the context of tax-related matters.
Options b and c are not accurate descriptions of the issue addressed in the Lowell Bar Association v. Loeb case. Therefore, option a is the correct and relevant choice.
Thus the correct option is A