Yuan Longping is a man who 1.w    the land, does his research and grows hybrid rice. He is an agricultural 2.p       . He 3.d      his whole life to finding ways to increase the rice output without 4.e       the area of fields. 5.T      to his research, more people can be free from 6.h     .Yuan is 7.s     with his life. He enjoys 8.l      to violin music. He cares little about his money and fame. He 9. t________ gives millions of yuan to 10. e_______     others for their research. He is a great person.

在燃油一定和风速不变的情况下，当飞机在逆风中飞行时，为了增大平飞航程，应该（）

A.减小空速

B.增大空速

C.保持空速不变

D.以上均可