# If the pair of lines $ax^2 + 2(a+b) xy + by^2 = 0$ lie along diameters of a circle and divide the circle into four sectors such that the area of one of the sectors is thrice the area of another sector, then :
( A ) $3a^2 - 2ab + 3b^2 = 0$
( B ) $3a^2 + 2ab + 3b^2 = 0$
( C ) $3a^2 + 10ab + 3b^2 = 0$
( D ) $3a^2 - 10ab + 3b^2 = 0$