请选择ABC'm6?0F0m0G7Q(` The bird is _______the tree.4K.G.v6n:f.F+_7m.\:q+Z
A. on4K.G.v6n:f.F+_7m.\:q+Z
B. 不填4K.G.v6n:f.F+_7m.\:q+Z
C. in4K.G.v6n:f.F+_7m.\:q+Z