What is the purpose of halyards on a boat?

The purpose of halyards on a boat is to raise and lower the sails, making option B the correct choice. Halyards are ropes or lines that are specifically designed to hoist sails up and allow them to be lowered when needed. This function is crucial for managing the sails effectively while sailing, as it enables the sailor to adjust the sail's position based on wind conditions or when coming into port.

Controlling the angle of the sails is done using different rigging and lines like sheets, which is why that option is not correct. Securing the anchor typically involves anchor lines or chains rather than halyards, and tying the boat to the dock is accomplished with docking lines, not halyards. Understanding the specific equipment and their functions is essential for safe and effective boating.