What three issues would render a ladder unfit for use?

The identification of three issues that would render a ladder unfit for use centers on safety and compliance with industry standards. A ladder that has been painted can be problematic because paint may obscure structural damage or defects. Additionally, non-industrial grade ladders (which are often meant for lighter duty) may fail under heavy loads, leading to potential accidents. Missing ropes and braces are critical since they provide essential stability and support; without them, the ladder can become unstable and unsafe for use.

These factors are vital to maintaining the integrity and safety of the ladder, thus making it unfit for use. It's essential to always ensure that ladders meet specific safety criteria to protect the user effectively. Other options may include issues that could affect usability or performance, but they don't encompass necessary safety standards in the same way.