Problem: Mary has owned her principal residence for over six years. Two years ago, she married John, who immediately moved into the residence. John has never used the Section 121 exclusion. If Mary sells the residence this year and John and Mary file a joint return, which of the following statements is CORRECT with respect to the availability of the Section 121 exclusion? A) The maximum exclusion is $500,000 because that is the amount always available for married taxpayers who file jointly. B) The maximum exclusion is $250,000 because that is the maximum exclusion for an individual who was single when the residence was purchased. C) The maximum exclusion is $250,000 because John is not an owner of the residence. D) The maximum exclusion is $500,000 because Mary has at least two years of ownership, and both spouses meet the use requirement.