What happens next?

How to troll on minecraft
You can make a simple obsidian trap, and it would be impossible to escape on survival.
You take a piece of flat land, about five squares to five squares. In each corner, you add three pieces of obsidian.

Choices:
[A]. Think of something round, but don't make it too round. At the corners, you add five cobblestone blocks..
[B]. Repeat this until you have a dozen to do with. Rock the two pieces of obsidian together..
[C]. The first square with the four pieces of obsidian is the hardest. This will work on the other two squares in the game..
[D]. After making four pillars, you then make a roof. Make it low enough, so you can't jump, but you can move around..
[D].