Why Can a Parent Corporation Cause Its Subsidiary to Transact

Why can a parent corporation cause its subsidiary to transact with it in a manner that benefits the parent but harms the subsidiary?

A) The parent corporation has commingled its assets with the subsidiary.
B) The parent owns a majority of the subsidiary's shares.
C) The parent is liable for its obligations and the subsidiaries.
D) The parent elects the directors of its subsidiary and therefore,can control the management of a subsidiary.