Which of the following statements is true

A．People cannot do without the wholesaler's function.

B．The function of the wholesaler does not add to the cost of goods.

C．The wholesaler helps to reduce the price of goods in shops.

D．The wholesaler is well paid for his commercial service.

需要与原发性骨质疏松症鉴别的疾病有（）

A.内分泌疾病（性腺、肾上腺及甲状腺和甲状旁腺疾病等）

B.类风湿关节炎等免疫性疾病

C.影响钙和维生素D吸收和调节的消化道与肾脏疾病

D.早期2型糖尿病或代谢综合征

E.多发性骨髓瘤和转移瘤等恶性疾病