Which of the following is a nonadjustable, single-section ladder?

• A. Step ladder
• B. Extension ladder
• C. Portable ladder
• D. Wall ladder

Answer: (D)

The main idea is recognizing ladders by whether their length is fixed and whether they’re mounted or portable. A nonadjustable, single-section ladder stays the same height and isn’t meant to be moved or extended; it’s a single rigid piece. A wall ladder fits this description because it’s attached to a wall and has a fixed length with no telescoping or folding sections. The other options involve moving or changing height: extension ladders are designed to telescope to different lengths, and step or portable ladders are designed to be moved and often include hinges or multiple parts, so they’re not just a single fixed section. So the wall ladder is the one that is nonadjustable and single-section.