Caterpillar Inc. reports a net income for 2016 of $2,700 million, retained earnings at the end of the year of $27,377 million, and declared dividends during the year of $1,802 million. What was the company's retained earnings balance at the start of 2016?

A. $28,275 million

B. $31,879 million

C. $28,275 million

D. $26,479 million