If the line y=mx bisects the angle between the line ax²+2h xy+by²=0 then m is a root of the quadratic equation :
A. hx²+(a−b)x−h=0
B. x²+h(a−b)x−1=0
C. (a−b)x²+hx−(a−b)=0
D. (a−b)x²−hx−(a−b)=0