Final answer:
A short piece of wall about as long as it is thick is called a pillar, which functions as a vertical support and can be made from materials like wood, brick, stone, or mud bricks. So, the correct option is Option 3: Pillar
Step-by-step explanation:
A short piece of wall that is approximately as long as it is thick is commonly referred to as a pillar.
This architectural element serves as a structural support and is usually vertical in design.
It can be constructed of various materials such as wood, brick, stone, or mud bricks.
In contrast to other structural elements like a post (which might be used similarly but is often made of wood and squared rather than rounded), a beam (which refers to a horizontal structure that usually supports the structure above), or a slab (which is a flat piece of material such as concrete), a pillar is characteristically round or polygonal and designed for support or ornamentation.
Therefore, the correct option is Option 3: Pillar