光学瓦斯检定器二氧化碳吸收管内装钠石灰，吸收二氧化碳由粉红色颗粒变为（）。

A、淡绿色

B、黑色

C、粉色

D、淡黄色

What（）to him is whether the job of a deck officer allows him to pursue his studies.

A.matters

B.happens

C.refers

D.applies