Which lines are used to control the angle of the sails to the wind?

The correct choice is sheets, as they are the lines specifically used to control the angle of the sails in relation to the wind. By adjusting the sheets, a sailor can trim the sails to either harness more wind for speed or reduce sail area to maintain control and stability in strong winds. This trimming is essential for effective sailing, allowing a vessel to navigate efficiently.

Halyards, on the other hand, are the lines used to raise and lower the sails, which is a different function from controlling their angle once they are set. Supports generally refer to structures that provide stability to the mast or rigging and do not directly influence sail angle. Shrouds are cables that support the mast from the sides and, while they contribute to the overall rigging and stability of the boat, they do not play a role in adjusting sail angle.