Article 336 of the Interpretation of the Criminal Procedure Law stipulates that the litigation representative of the defendant unit is the legal representative, actual controller or principal responsible person; If the legal representative, actual controller or principal responsible person is accused of being the direct responsible person of the unit crime or unable to appear in court due to objective reasons, the defendant unit shall entrust other responsible persons or employees as litigation agents. However, unless accused of being directly responsible for the unit crime or knowing the case and having the obligation to testify. If it is difficult to determine an agent ad litem in accordance with the provisions of the preceding paragraph, the defendant unit may entrust a person from a unit other than a lawyer as an agent ad litem. An agent ad litem shall not act as the defender of the defendant unit or the relevant personnel accused of being directly responsible for the unit crime at the same time. It can be seen that the litigation representative of the defendant unit is only the person who exercises litigation rights on behalf of the defendant unit, not the defendant. Therefore, item A is wrong. Item b is correct. Article 337 of the Interpretation of the Criminal Procedure Law stipulates that when trying a unit crime case, the litigation agent of the defendant unit shall be notified to appear in court; If there is no agent ad litem to participate in the proceedings, the people's procuratorate shall be required to determine. If the litigation representative of the defendant unit does not appear in court, it shall be handled according to the following circumstances: (1) The litigation representative is the legal representative or principal responsible person of the defendant unit, and if he refuses to appear in court without justifiable reasons, he may be summoned to appear in court; If he cannot appear in court or his whereabouts are unknown due to objective reasons, he shall request the people's procuratorate to appoint another agent ad litem; (2) If the agent ad litem is someone else, the people's procuratorate shall be required to appoint another agent ad litem to appear in court. Because Huang is not allowed to be the litigation representative of the company, item C is incorrect and item D is correct. The correct answer to this question is AC.