单项选择题
A. qj.aviB. qj.rmC. qj.rmvbD. qj.jpg
A.(x+y)(x-y)/Abs(x)+y*y B.(x+y)(x-y)/(Abs(x)+y*y) C.(x+y)*(x-y)/(Abs(x)+y*y) D.(x+y)*(x-y)/(Sqr(x)+y^2)