What effect does increasing the number of parts of line have on the load being lifted?

Increasing the number of parts of line in a rigging system directly affects the load being lifted by distributing the weight more effectively across the rigging components. This setup allows the system to handle a greater load capacity because each part of the line contributes to supporting the total weight.

With more parts of line, the overall force exerted on each individual line decreases, which means that the rigging system can lift heavier loads without exceeding the safe working limits of any single component. This characteristic makes multi-part systems advantageous for lifting applications where weight management is crucial.

By contrast, the other options do not accurately reflect the principles of rigging. Increasing parts of line does not inherently decrease lift efficiency, require more operator training, or simply reduce stress on rigging without a broader context of how they are applied, as those aspects involve various factors beyond just the number of parts of line.