A very comfortable type of stairs is

ANS:D - open newel.

Open newel stairs refer to a specific type of staircase design characterized by an open space or void in the center of the staircase, where the newel post (a central supporting pillar) is left open or absent. This design feature offers several advantages that contribute to the comfort and aesthetics of the staircase:

1. Enhanced Visibility and Airiness: The absence of a central newel post in open newel stairs creates an open and airy feeling in the staircase. This design allows natural light to penetrate the space more freely and provides unobstructed views throughout the staircase, promoting a sense of spaciousness and visibility. As a result, users ascending or descending the stairs may feel more comfortable and less confined.
2. Improved Accessibility: The open space in the center of open newel stairs can improve accessibility and maneuverability, especially for individuals with mobility limitations or those carrying bulky items. The absence of a central pillar allows for more freedom of movement and makes it easier to navigate the staircase, particularly in the case of wider staircases where multiple people may be using the stairs simultaneously.
3. Architectural Elegance: Open newel stairs often possess a visually striking and architecturally elegant appearance. The open void in the center of the staircase creates a distinctive focal point that can enhance the overall aesthetic appeal of the space. This design feature is favored in many contemporary and modern architectural styles for its aesthetic value and ability to add character to interior spaces.
4. Design Flexibility: Open newel stairs offer design flexibility, allowing for customization and adaptation to various architectural styles and interior design preferences. Designers and homeowners have the freedom to incorporate additional design elements such as decorative railings, balusters, or lighting fixtures to further enhance the visual appeal and functionality of the staircase.

Overall, open newel stairs are valued for their combination of aesthetics, functionality, and comfort. By creating a sense of openness, improving visibility and accessibility, and offering design versatility, open newel stairs can contribute to the overall comfort and appeal of a building's interior space.