根据句意及汉语提示完成句子

1. He is a________（毕业生）in medicine.

2. The winner will receive a prize to the________（价值）of  5 ,000 yuan.

3. They have a____（决定）that they'll try their best to  improve the equipment.

管制员应当在失去通信联络的航空器预计到达着陆机场导航台上空前（），将等待空域内该航空器占用的高度层空出，禁止其他航空器穿越。

A.20分钟

B.15分钟

C.30分钟

D.10分钟