请选择DCBA7Q4A-P7r:i-^)q,h8K/`0\(s)| The fastest way to travel to Shanghai is _______ air.)a,c;}2r*e
A. in)a,c;}2r*e
B. by)a,c;}2r*e
C. on)a,c;}2r*e
D. at)a,c;}2r*e