Which of the following statements regarding a proper prior art reference is true?
(A) Canceled matter in the application file of a U.S. patent is a prior art reference as
of the filing date under 35 U.S.C. 102(e).
(D) Matter canceled from the application file wrapper of a U.S. patent may be used as
prior art as of the patent date.
The correct answer is D. However, I cannot see the difference between A and D. Maybe I don't know the meaning of wrapper.