These lines are used to represent symmetry and paths of motion and to mark the centers of circles and the axes of symmetrical parts.

Centerline

Explanations: Centerline is a line that used to show symmetry and paths of motion and the centers of circles and the axis of symmetrical paths,Centerline can also be described as a that can be seen at an equidistant from the sides of a boundary,it is used to show where equal distributions have been achieved. Centerline can be real or Imagery, the concept of Centerline in geometry was introduced by Kimberly Clark. Check that attached, the centerline is the horizontal LINE BCA and the vertical LINE running through FC.

it is the second option.

it breaks and dirupture other materials and other sencews from the bottom