The requirement that there should be reasonable support for a tax return position before a CPA recommends it to a client most directly aligns with which tax standard?

a. There is a realistic possibility of success if the tax position is challenged

b. Contingent fees cannot be accepted when providing tax services for an audit client

c. It is more likely than not that the tax position will be upheld if challenged

d. The tax return should not be based on a frivolous position