What is the IRS guideline for determining whether a tax return position has substantial?authority?

What is the IRS guideline for determining whether a tax return position has substantial authority? O A. A person knowledgeable in the tax law concludes that the position has at least a two - thirds likelihood of being supported. O B. A person knowledgeable in the tax law concludes that the position has at least a 50% likelihood of being supported. O C. A person knowledgeable in the tax law concludes that the position has a something less than 50% likelihood of being supported. O D. A person knowledgeable in the tax law concludes that the position has at least a 75% likelihood of being supported