On December 31, 2012, after receipt of his share of partnership income, Clark sold his interest in a limited partnership for $30,000 cash and relief of all liabilities. On that date, the adjusted basis of Clark’s partnership interest was $40,000, consisting of his capital account of $15,000 and his share of the partnership liabilities of $25,000. The partnership has no unrealized receivables or appreciated inventory. What is Clark’s gain or loss on the sale of his partnership interest?