What component prevents the center pin from turning in a block configuration?

The component that prevents the center pin from turning in a block configuration is the strap. The strap is designed to secure the center pin in place, ensuring that it cannot rotate. This is crucial in maintaining the stability and proper functioning of the block, as any movement of the pin could lead to failures or inefficiencies during lifting operations. The strap effectively confines the movement, providing a more reliable rigging system.

The other options do provide certain functions, but they do not serve to restrict the rotation of the center pin. The king typically refers to a larger structural part where rigging components are attached, while the rope is used for lifting and does not interact with the center pin in terms of preventing rotation. The housing shell encases the components of the block but does not specifically control the pin's movement, as its role is more about structural integrity and protection.