The purpose of this question is to examine the examinee's mastery of the basic knowledge of bile production. Bile is stored in the gallbladder; From the point of view, bile is attached to the short lobe of the liver, and bile comes from the liver and is secreted by the liver to help digestion, so bile is accumulated by the excess gas of the liver. The secretion and excretion of bile depends on the release of liver qi. Bile is produced and stored in bile, and the liver also regulates bile excretion. Therefore, ancient physicians believed that bile was generated by the excess gas of the liver, and the bile hidden in bile was also called essence juice. Therefore, gallbladder, also known as "the viscera of the middle essence" in option B, is composed of the pure qi of breathing and the essence of Shui Gu in the chest; The ying qi in option C is the qi in blood, which is generated by Shui Gu's subtle; The essence of the spleen and stomach mentioned in option d is the qi that nourishes the viscera.