Which areas should be inspected on the watercraft?

The correct answer encompasses a thorough inspection focus on all critical components of the watercraft, ensuring comprehensive monitoring for any potential invasive species. By inspecting the hull, trailer, through hull fittings, and motor, this choice guarantees that all areas where aquatic hitchhikers could be present are checked.

The hull can harbor organisms attached to its surface, while the trailer might carry debris or organisms from previous water bodies. Through hull fittings are particularly crucial since they connect the watercraft to the water and can sometimes allow organisms to enter or escape. The motor also requires inspection as it can trap organisms in the cooling system or other components.

This detailed approach is vital for effective prevention of invasive species, aligning with best practices in aquatic resource management and ensuring compliance with inspection requirements. Other options fall short by omitting essential components of the watercraft that could carry aquatic invasive species, thereby failing to provide a comprehensive inspection.