Which of the following lenses should be used to correct the defect of astigmatism?

A cylindrical lens (option A) is used to correct the defect of astigmatism. Astigmatism occurs when the cornea or lens of the eye is unevenly curved, causing blurred or distorted vision at both near and far distances. A cylindrical lens has different powers in different meridians, often correcting the irregular curvature of the eye by compensating for the specific directions of curvature that cause astigmatism. By selectively focusing light along one axis more than the other, the cylindrical lens helps to bring light rays from different directions into focus on the retina, resulting in clearer vision. This correction is distinct from the use of concave (option B) or convex lenses (option C), which are typically used to correct nearsightedness or farsightedness, respectively. Bifocal lenses (option D) are used to correct presbyopia, a condition where the eye loses its ability to focus on nearby objects due to aging.