[单选题]
99.06: An airplane with air speed 1hk-l ky6d u7g p.hux9-qu6f0 f20 km/h 2treawf:j/ll8x tng3v d46 6ris heading due north in a wind blowing due east at 50 km/h. What is the grounf8d4tt err6 l/anw2 l:vj3g6 xd speed of the plane?
A. 60 km/h
B. 120 km/h
C. 130 km/h
D. 140 km/h
E. None of these
