What Is the "All Holders Rule" of the Securities and Exchange

What is the "all holders rule" of the Securities and Exchange Commission?

A) That an offer to purchase one class of stock must be extended to cover all classes of stock.
B) That a selective stock repurchase plan is deemed a tender offer in which all holders of securities of the same class must be allowed to participate.
C) That all directors holding stock in a corporation must withdraw from consideration of a hostile takeover bid.
D) That all officers holding stock in a corporation must refrain from giving advice to directors during a hostile takeover bid.