Concerning Treasury Shares, Which of the Following Is/are True

Concerning treasury shares, which of the following is/are true?

A) Firms recognize no gain or loss from purchasing their own shares or reissuing previously purchased shares.
B) Differences between the purchase and reissue price are not earnings transactions but affect contributed capital accounts.
C) Firms account for the purchase of treasury shares using either the cost method or the par value method or the constructive retirement method.
D) The methods firms use to account for the purchase of treasury shares differ in terms of the shareholders' equity accounts affected, but all result in an equal reduction in total shareholders' equity when firms purchase their own shares.
E) all of the above