Chana contributed $6,000 for a 50% interest in a mobile clothing boutique. She also contributed a point of sale system with a fair market value of $900 and an adjusted basis of $600. During the year, the boutique earned a profit of $18,000. What is Chana's partnership basis in this business at the end of the year? A) $6,000; B) $9,000; C) $15,600, D) $15,900.