Martha, an accrual-method taxpayer, has an accounting practice. In 2012, she performs tax analyses for Arnold and sends him an invoice for $10,000. In 2013, Martha sells her practice and all accounts to David. Arnold's debt becomes worthless that year. The result is (Points : 4)

Martha deducts a nonbusiness bad debt in 2013. Martha deducts a business bad debt in 2013 David deducts a business bad debt in 2013. David deducts a nonbusiness bad debt in 2013.