According to the Government Procurement Law of the People's Republic of China*** and the People's Republic of China:
"Article 53? The procurer shall respond to a written challenge from a supplier within seven working days after receiving it and notify the challenging supplier and other relevant suppliers in writing, provided that the content of the response shall not involve commercial secrets."
Expanded information:
"Article 55? A questioning supplier who is dissatisfied with the response of the purchaser or the purchasing agent or the purchaser or the purchasing agent fails to make a response within the prescribed time may file a complaint with the government procurement supervision and management department at the same level within fifteen working days after the expiration of the response period."