A. It belongs to the infringement of name right, and infringement of name right does not belong to the category of infringement of intellectual property rights.

B. Although Party A sells high imitation leather bags, which are hard to distinguish between true and false, and no losses have been caused, according to Article 56 of the Trademark Law, it is not liable for compensation if it can prove that it was legally obtained by itself and explained to the supplier by selling goods that it did not know were infringing the exclusive right to use a registered trademark. "The premise of not being liable for compensation in the interpretation is infringement, but because it is unknowable, it is not liable for compensation, but the behavior is still infringement.

C.A develops the game of "A's C", but the trademark right of "AC" belongs to B, so there is a question whether "A's C" and B's "AC" are the same or similar. At the same time, does B's "AC" trademark include the category of the game? Assuming that C of A is very similar to AC, and the game category was included at the time of registration, then A has the problem of infringement.

D. AC musical instruments are different from AC computers. Moreover, trademark registration has nothing to do with infringement. The so-called infringement must be that the trademark used in the commodity infringes the existing trademark right. If Party A only registered the trademark and didn't use it, there is no infringement involved.