The correct option is D (1,−2)
Let, y=mx+c is a equation of chord.
∵y−mxc=1
By homogenization,
3x2−y2−2x(y−mxc)+4y(y−mxc)=0
3cx2−cy2−2xy+2mx2+4y2−4mxy=0
(3c+2m)x2−(c−4)y2−(2+4m)xy=0
So, angle between these lines is given by
tanθ=∣∣∣2√(1+2m)2−(3c+2m)(4−c)(2c+4+2m)∣∣∣
Given. θ=90∘,
∴2c+2m+4=0
−2=m+c
y=mx+c
y=−2 & x=1