You'd sound a lot more polite if you make a request _____ a question. [ ]

A. in search

B. in the form of

C. in need of

D. in the direction of

一类疫病是指（）需要采取紧急、严厉的强制预防、控制、扑灭措施。

A.对人畜危害严重

B.可造成重大经济损失

C.常见多发，可能造成重大经济损失

D.可能造成一定经济损失