亚急性细菌性心内膜炎的发生

A．由致病力强的化脓菌引起
B．由致病力弱的草绿色链球菌引起
C．与A组溶血性链球菌感染有关
D．与系统性红斑狼疮有关
E．与慢性消耗性疾病有关

All else being equal, an increase in the price of one product will most likely cause the demand curve of the product's supplement to:（）

A. Remain unchanged.

B. Shift upward and to the right.

C. Shift downward and to the left.