This question involves the agency system of trademark registration application. Article 18 of the Trademark Law stipulates that if a foreigner or foreign enterprise applies for trademark registration and handles other trademark matters in China, it shall entrust a legally established trademark agency to handle it, so item A is correct. Article 17 of the Trademark Law stipulates that if a foreigner or foreign enterprise applies for trademark registration in China, it shall be handled according to the agreement signed between the country to which it belongs and China, or the international treaties to which it is a party, or according to the principle of reciprocity, so item B is wrong. Article 19 of the Trademark Law (revised in 219) stipulates that if a trademark agency knows or should know that the trademark applied for registration by a client falls under the circumstances specified in Articles 4, 15 and 32 of this Law, it shall not accept its entrustment. Article 32 stipulates that the application for trademark registration shall not damage the existing prior rights of others, nor shall it preempt the registration of trademarks that others have used and have certain influence by improper means, so item C is correct. Intellectual property rights are regional, and whether an application for a registered trademark in China can be registered is completely reviewed in accordance with the standards stipulated by Chinese laws. Therefore, the country to which Company A belongs rejected its application for trademark registration, which does not affect the identification of its application in China, so item D is wrong. Therefore, the correct answer to this question is AC.