In one-point perspective, depth lines converge at a single vanishing point on the horizon line. This vanishing point sits at the viewer’s eye level and is the place where all lines receding into space meet, giving the sense that the scene extends directly away from the viewer. Objects facing you project their depth toward that one point, while vertical edges remain vertical and horizontal lines angle toward the vanishing point. This is why the correct idea is that there is one vanishing point on the horizon line. The other choices describe different concepts: two vanishing points belong to two-point perspective, while shading techniques like cross-hatching and color mixing techniques are unrelated to how perspective lines converge. Imagine a road or railroad tracks receding straight ahead; the edges appear to meet at a single dot on the horizon.