Which line use can increase both depth and mystery in a picture?

Correct answer: Light and faint lines in distant parts

The correct answer is A. In a picture, distant forms are often suggested with lighter, thinner, softer, or less definite lines. This reduces their visual strength and helps create a sense of space, so the viewer reads them as farther away. Faint lines can also leave some information uncertain, and that partial uncertainty may add a quiet or mysterious mood. A does not guarantee mystery in every artwork, but it is the option that can support both depth and ambiguity. B is wrong because a dark boundary around every part gives all objects equal strength and can flatten the spatial effect. C is wrong because erasing the main part removes information rather than carefully creating depth. D is wrong because equal thick lines usually reduce atmospheric difference between near and far areas. Memory cue: distant and uncertain—lighter and less definite.