Step-by-step explanation:
a) Line BD is an angle bisector. It divides the angle at B into equal halves.
BD is also a median of the triangle as the line starts from th vertex and divides the opposite side into two equal parts.
Angle bisector of ∠B
median of triangle ABC
b) HI is a perpendicular bisector of line FG. It makes angle 90 degrees with the base.
HI is also an altitude of triangle FGH
c) MN is not a median of triangle JKL as the line doesnot start from the vertex of the triangle
MN is a perpendicular bisector of line KL