Answer:
The correct answer is letter "D": None of the above.
Explanation:
Even if John has no direct either indirect influence in the business it is not suitable for him to accept the gift from his friend. The position John's friend has in the supplier company is unknown which implies his friend could play a managerial role, therefore, it is better to avoid any type of action that could be a signal of preference towards that company.
Besides, John works in accounting which is an administrative department of the business, thus, John should be extra careful in his actions regardless of the influence he might have in the firm.