On December 31, 2010, the net assets of Marino Manufacturing amounted to $40,000. Net income calculated by using the financial capital maintenance concept amounted to $12,000. During the year, additional common stock was issued for $8,000, and $5,000 of dividends was paid. The net assets at January 1, 2010, amounted to:
a) $31,000
b) $37,000
c) $20,000
d) $25,000