Even though the producer surplus increases under a monopoly scenario, relative to one of perfect competition, the consumer surplus :（）

A. decreases by a lesser amount.

B. decreases by a greater amount.

C. decreases by an equal amount.

下列说法错误的是（　　）

A．中和反应一定是复分解反应

B．化学反应前后原子个数一定相等

C．非金属氧化物一定是酸性氧化物

D．氧化物一定是化合物