A. Angle bisectors
D. Perpendicular bisector
The question was asked by my school teacher while I was bunking the class.
My question comes from Drawing Tangents and Normals for Different Conditions of Circle topic in section Geometrical Construction of Engineering Drawing
To elaborate: To draw a tangent to an arc of an unknown radius and a centre through any point on the arc we the principle of perpendicular bisectors. First, we cut the arc at two sides of the point by an arc of any radius and we use perpendicular bisector to draw the normal and from there we draw the tangent.