The correct answer is D, Trichinella spiralis.  This case of trichinellosis was caused by eating bear meat containing larvae of T. spiralis (sensu lato).  Larvae of T. spiralis were recovered by digestion of the suspect bear meat.  In the United States and other countries, control of trichinellosis has been achieved through a combination of factors, including a decrease in the prevalence of infection in market hogs.  However, wild animals continue to harbor infections and serve as a source of human infection when meat products are poorly cooked.