U.S. Digital Corporation incorporated in Ohio, its only place of business. Its stock is owned by ten shareholders. Two are resident aliens. Three of the others are the directors and officers. The stock has never been sold to the public. If a shareholder wants to sell their shares, the other shareholders must be given the opportunity to buy them first. U.S. Digital is

a. a close corporation.

b. a foreign corporation.

c. an alien corporation.

d. none of the above.