Which use of lines helps make a figure look more realistic?

Drawing lines according to surface curves

Lines that follow the curves and direction of a surface help the viewer understand its form and volume. For example, curved marks around a rounded object can suggest that the surface turns, while directional lines on a cylinder or cloth can describe its structure. This makes the figure appear more three-dimensional and realistic, so option A is correct. Keeping every line in one direction may ignore the object’s surface, and writing a name or omitting lines cannot describe form. The marks should be observed and adjusted to the object; line direction, curvature, spacing, and pressure can work together to suggest depth and solidity.

This is a Class 9 Art Education question. Chapter: Elements of Art. Topic: Line.