[单选题]
Compared to the velocity of a 400ks;.1ux x8xy5 mouz80mehtnp1 o8x2k Hz sound, the vel,imz :u/pbcr( :kg lq5 ak9/z()gp rdeocity of a 200 Hz sound through qpdk cl 9/kb,e/(pza5)g::m gurzir(air is
A. twice as great.
B. the same.
C. one-half as great.
D. none of the above
