Two sources of error and precaution in the centre of gravity experiment

The answer to this question is given below in this explanation sections.

Explanation:

The weight of an object is concentrated at the center of gravity.The term center of gravity is used interchangeably with center of mass.For a symmetrical object the center of mass is located  at the geometric  center of the object.If the object is not symmetric we can determined the center of mass using the mentioned below.

Materials:

cardboardweight(washer,bolt,or fishing weight)hole punchpencil

Procedure:

Cut the cardboard into a strange shape.Do not use a circle,square,rectangle,or any other common geometric shape.Punch a hole near the edge of the cut-out cardboard piece and hang it from a nail.Place the weight, a washer or bolt, on a thread and tie it off.Hang the thread and weight from the nail in front of the cardboard.use a pencil to draw a plumb line down the cardboard where the thread touches.This mark your center  line from that hanging point.

conclusion:

             What would happen to the center of gravity of the shape if you were to spin it freely?

center of gravity experiment:

Balance a ruler with a hammer.Take a rubber band or string and make a loose loop around the hammer and ruler. Make sure the end of the hammer is touching the ruler,and then positions the ruler at the edge of the table.Balance two forces with  a toothpick.A common magic  trick using the properties of center of gravity.The two forks are balanced on the edge of the glass by a toothpick. Stand with your back and feet against a wall.Have someone place quarter on the floor at your feet.Try to pick it cup.Most people cant make these adjustments.Stand against a wall sideways with your arm and leg touching the wall,with nothing to from the out away hold onto.Try to lift your other leg straight out away from the wall.you wont be able to do it.The girls away win chairs lifting challanges place dining chairs against a wall.Bend over the chair so that your head touches the wall and you upper body is parallel to the floor.lift the chair to your chest to your chest and then try to stand up.

My answer is opptionc, just check with anyone else