Explanation:

Stairs:
Stairs are a series of steps that allow people to move between different levels within a building. They are an essential component of most buildings and are designed to provide a safe and convenient means of vertical circulation.

Types of Stairs:
There are several different types of stairs, each with its own unique design and characteristics. Some common types of stairs include:

1. Full Turn:
- Also known as a U-shaped staircase, a full turn staircase is characterized by a 180-degree turn.
- It typically consists of two straight flights of stairs connected by a landing in the middle.
- This type of staircase is commonly used in residential buildings and can be visually appealing.

2. Open Newel:
- An open newel staircase is characterized by an open space between the treads.
- It typically has a central support column called a newel post, which provides stability and structural integrity.
- This type of staircase is often used in older buildings and can have a traditional or decorative design.

3. Dog-legged:
- A dog-legged staircase is characterized by two flights of stairs that are parallel to each other and connected by a landing.
- It is called dog-legged because the two flights resemble a dog's hind legs.
- This type of staircase is commonly used in residential buildings and can save space compared to a full turn staircase.

4. Three Quarter Landing:
- A three quarter landing staircase is characterized by three flights of stairs that are connected by two landings.
- It typically forms a 90-degree turn, with two flights running parallel to each other and the third flight perpendicular to them.
- This type of staircase is often used in commercial buildings and can provide a visually interesting design.

Conclusion:
Among the given options, the type of stairs that is not present is "Full Turn" (option A). Full turn stairs are a common type of staircase, and they are not included in the options given. Therefore, option A is the correct answer.