— ______ .
A：Yes, they are
B：No, it isn't
C：It's a yellow monster
亚硝酸钠（NaNO2）是一种常用的防腐剂，有咸味，易溶于水，有毒．在320℃时分解生成有刺激性气味的气体，与盐酸作用会放出红棕色气体．亚硝酸钠在食品中的添加量必须严格控制．下列说法不正确的是（ ）
Our hospital needs two doctors, Mrs Li. You can ask your son to have a try.
