Which of the following does not require a license to operate?

The non-cab operated category 3 bridge crane does not require a license to operate primarily because it typically has limited functionality compared to other types of cranes that do require licensing. These cranes are usually designed for straightforward operations in controlled environments and are often used for moving materials within a specified area, such as in warehouses or manufacturing plants.

The regulations surrounding crane operation generally focus on ensuring that operators possess the necessary skills and knowledge to handle complex machinery safely. Cranes that involve heavy lifting, mobile operation, or more complex mechanisms, like the cab-operated category 3 bridge crane, mobile hydraulic truck cranes, and articulating boom category 4 cranes, require operators to have specialized training and licenses to ensure safety and compliance with local regulations.

By contrast, non-cab operated cranes usually have simpler controls and limited application, thus reducing the need for a licensed operator. However, it's essential for all crane operators to still be familiar with safety practices and operational protocols, even if formal licensing is not mandated.