Bill Johnson's will provided that $10,000 a year would be paid to his widow and $5,000 a year to his son out of the estate's income. There were no charitable contributions made. If the estate's distributable net income for the year was $12,000, how much of the distribution to Bill's son is taxable to him? A. $5,000 B. $8,000 C. $10,000 D. $4,000