Delta Corporation Owns 90% of Sigma Company, and Sigma Owns

Delta Corporation owns 90% of Sigma Company, and Sigma owns 90% of Pi, Inc., all of which are domestic corporations. There are no excess amortizations associated with any of the acquisitions. Information for the three companies for the year ending December 31, 2021 follows: Which of the following statements is true?

A) Delta and Sigma must file a consolidated income tax return, but must exclude Pi from the consolidated return.
B) Delta, Sigma, and Pi must file a consolidated income tax return.
C) Delta, Sigma, and Pi must file separate income tax returns because the ownership of Sigma and Pi is less than 100%.
D) Delta, Sigma, and Pi will probably not file a consolidated income tax return.
E) Delta, Sigma, and Pi may file separate income tax returns or a consolidated income tax return.