The most often used application of the term virtuosity applies to music - a virtuosic piece, a virtuosic musician etc. Thus the answer to this is b. Virtuosity means extreme technical proficiency in an area of music (though it can be applied to other things as well to show mastery of a skill - a virtuosic painter etc.)
A mistake involving the misunderstanding or incorrect application of law with regard to an act or transaction. The defense of mistake of law raises two issues. The first issue occurs where, because of a mistake of law, the defendant did not have the requisite intent to commit a crime.
