Which of the following would cause a revocation of S status for an existing S corporation?

I. A partnership becomes a shareholder of an S corporation

II. An S corporation becomes a partner in a partnership

III. An S corporation becomes a shareholder in a C corporation

IV. A nonresident alien becomes a shareholder of an S corporation

a. None of the above

b. II and III

c. I and IV

d. All of the above