Final answer:
The cousin's stock ownership impairs the firm's independence due to the partner's financial support, whereas the father's stock ownership does not affect independence as there is no financial dependency or influence over the company.
Step-by-step explanation:
When assessing the independence of an audit firm with respect to its client, it is crucial to consider both direct and indirect financial interests that could be perceived as impairing independence. In the scenario provided, the partner does not support the father who owns 400 shares of Atlas Mfg. Co. Therefore, as it is not material to the father and he does not have any influence over the company, the father's stock ownership does not impair independence. However, the partner fully supports the cousin who owns 30 shares. Since the partner's financial support could be seen as an indirect financial interest through the cousin, this could potentially impair the firm's independence.
The correct answer is A. I only, meaning that only the cousin's stock ownership impairs the audit firm's independence with Atlas Mfg. Co.