Answer: b. The company issued common stock in 2015.
Step-by-step explanation:
Common Stock is recorded at par value in the books and so the only things that can affect it are more stock being issued which would increase it or treasury stocks being purchased which would decrease it.
As the common stock increased in 2015 from 2014 by $1,000 more, it shows that the company issued $1,000 worth of stock in 2015.