Answer:
A. an individual, Mr. Rupert, who has a lot of experience in handling taxes, but is not affiliated to any big firm
Step-by-step explanation:
Xenon does not have experience in tax-related queries. Hence, it's not a good choice. Radon also has only some experience in handling taxes, though it has discouraging references. Hence, he is also not a choice. Argon is from another state, though it has a good website. But the website cannot be an option, And hence, Mr. Rupert which has a lot of experience in handling taxes is the right option for you. However, Experience is more important than the firm.