The word "plagiarize'(Line 6, Para 5) most probably means"______".

A．When a patent becomes out of effect, it can be re-patented or extended if necessary.
B．One can get all the details of a patented invention from a library attached to the patent office.
C．A patent holder must publicize the details of his invention when its legal period is over.
D．An inventor needs to apply for a patent before he makes his invention public.

A．an invention will not benefit the inventor unless it is reduced to commercial practice
B．patent experts often recommend patents to others by conducting a search through dead patents
C．an old patent is more expensive than a new one
D．products are actually inventions which were made a long time ago