Where the Bylaws Require a Simple Majority Vote of Shareholders

Where the bylaws require a simple majority vote of shareholders for a particular action,what is the legal significance of a unanimous vote instead of simple majority vote?

A) There is no difference in the legal effects of the two votes.
B) The directors can override the vote if it is less than unanimous.
C) The vote could be reversed at a later shareholders' meeting if it is less than unanimous,but not if it is unanimous.
D) The dissenting shareholders can demand that the corporation repurchase their shares in a less than unanimous vote,but this would be inapplicable in a unanimous vote.