Which of the Following Statements Is Incorrect with Respect to Parent-Subsidiary

Which of the following statements is incorrect with respect to parent-subsidiary corporations?

A) With a consolidated return,net losses of one company can offset net income from another company.
B) A parent-subsidiary group must file a consolidated tax return.
C) A parent-subsidiary group is one where a common parent corporation owns,directly or indirectly,at least 80% of one or more other corporations.
D) If a consolidated tax return is filed,losses on intercompany sales cannot be immediately recognized.