Why can a heavy outline be a problem when showing transparency of an object?

It can make the object look solid and heavy

The governing concept is that line quality should communicate material quality. A transparent object, such as clear glass, is suggested by delicate edges, selective contours, visible overlaps, and carefully preserved light areas. A very dark or heavy outline gives the boundary excessive visual weight and makes the object read like an opaque, solid form. Thus option A is correct: the outline can make the object appear dense and heavy, reducing the intended sense of transparency. Option B is wrong because stronger outlining does not automatically increase transparency. Option C is nonsensical; an outline cannot turn an object into air. Option D is also incorrect because highlights must be planned through light areas and contrast; they are not created automatically by a thick contour.

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