Koch Industries ("Koch") is a closely held 'S corp.' that meets the qualifying requirements of the Internal Revenue Code.Koch's Board of Directors hold a special meeting to consider options to raise funds for future growth. Which of the following actions might put Koch's sub-chapter S tax treatment election at risk with the IRS:

a.Koch issues shares to 200 new shareholders.

b.Koch authorizes a second class of stock.

c.Koch adds a foreign national shareholder/investor.

d.All of the above.