This topic examines trademark registration and examination, and is an important examination center.

According to Article 8 of the Trademark Law, any sign that can distinguish the goods of natural persons, legal persons or other organizations from the goods of others, including words, graphics, letters, numbers, three-dimensional signs, color combinations and sounds, and the combination of the above elements, can apply for registration as a trademark. Therefore, the sound can be registered as a trademark, so option A is correct. According to the provisions of Article 22 of the Trademark Law, the applicant for trademark registration shall fill in the category and name of the goods using the trademark in accordance with the prescribed commodity classification table and apply for registration. An applicant for trademark registration may apply for the registration of the same trademark for many kinds of goods through one application. So option b is wrong. According to item 10 of Article/kloc-0 of the Trademark Law, the following marks shall not be used as trademarks: (1) They are identical with or similar to People's Republic of China (PRC)'s national name, national flag, national emblem, national anthem, military flag, military emblem, military songs and medals, and the names, signs, names or symbols of central state organs. Therefore, the c option is correct. According to Article 14 of the Trademark Law, producers and operators shall not use well-known trademarks in commodities, commodity packages or containers, or in commercial activities such as advertisements and exhibitions. Therefore, the d option is correct.

To sum up, the answer to this question is ACD.