Which of the Following Is Not a Reason for a Parent

Which of the following is not a reason for a parent to lose control of a subsidiary?

A) when the parent makes a decision to sell its controlling interest in the subsidiary to another party
B) where the subsidiary issues additional shares to parties other than the parent
C) the expiry of a contractual agreement that previously permitted the parent entity to control a subsidiary
D) All of the choices could be a reason for the parent to lose control.