Saira's Maid Service began the year with total assets of $120,000 and stockholders' equity of $40,000. During the year the company earned $90,000 in net income and paid $20,000 in dividends. Total assets at the end of the year were $215,000. How much was stockholders' equity at the end of the year?
A. $130,000
B. $110,000
C. $150,000
D. $135,000