The combined equation of the lines `L_(1)` and `L_(2)` is `2x^(2)+6xy+y^(2)=0` and that lines `L_(3)` and `L_(4)` is `4x^(2)+18xy+y^(2)=0`. If the angle between `L_(1)` and `L_(4)` be `alpha`, then the angle between `L_(2)` and `L_(3)` will be
A. `(pi)/2-alpha`
B. `(pi)/4+alpha`
C. `2alpha`
D. `alpha`
