为了了解参加全运会的2000名运动员的年龄情况，从中抽查了100名运动员的年龄，则样本的容量是（    ）。

If you tend to regularly suffer from a certain symptom like headache, be sure to keep in store the

       medicine to take care of the issue as soon as it starts.

A．efficient

B．concise

C．appropriate

D．secure