Kirk, an accrual-basis taxpayer, owns a small record store as a sole proprietor. Which of the following may be deducted as a business bad debt? A Worthless loan to his son for college tuition: $1,500. B. Worthless trade receivable: $3,000. oc. Partially worthless note from a friend: $1,200. D. Payment of a $7,500 loan he had guaranteed for a friend (not connected to Kirk's business)