Gavin Owns a 50% Interest in London Partnership $\quad$ $\quad$ $\quad$

Gavin owns a 50% interest in London Partnership. His tax basis in his partnership interest at the beginning of the year was $20,000. His partnership Schedule K-1 showed the following:
Ordinary business income $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ $ 60,000
Share of partnership debt, beginning of year $\quad$ 10,000
Share of partnership debt, end of year $\quad$$\quad$$\quad$ 15,000
Calculate Gavin's tax basis in his partnership interest at the end of the year?

A) $85,000
B) $95,000
C) $75,000
D) $65,000