can someone pls explain this

1. You stand with your back against a wall, with your heels touching the wall. Now, while keeping your legs straight, you try to touch your toes. What happens? (a) It is the same situation as without the wall. (b) The vertical line through my centre of mass moved to behind the heels of my feet and I fell forward. (c) The vertical line through my centre of mass moved beyond the toes of my feet and a I fell forward. (d) The vertical line through my centre of mass moved beyond the toes of my feet and a I fell backward. (e) The vertical line through my centre of mass moved to behind the heels of my feet and I fell upward. 2. An suitable explanation for the wine bottle balancer is: (a) Some wine was spilt and the wood got stuck to the bottle and to the table. (b) The vertical line through the centre of mass of the wood passes through the base of the wood. (c) The vertical line through the centre of mass of the bottle passes through the base of the wood. (d) The vertical line through the centre of mass of the combined bottle+wood system passes through the base of the wood. 0:) It's magic