Which answer clearly explains the use of line?

Correct answer: Diagonal lines show the movement of a running player

Direct answer: A, because it identifies a type of line and explains its visual effect. Lines can be horizontal, vertical, diagonal, curved, thick, thin, continuous, or broken. Their direction and quality can guide the eye and suggest movement, stillness, strength, softness, or emotion. In option A, diagonal lines are the observed element and movement is the effect that they help communicate in the picture of a running player. Option B only states where horizontal lines are located; it does not explain what those lines do or suggest. Option C discusses colour, not line. Option D describes facial expression, which is part of the subject or emotion, but it does not analyse the use of line. A common mistake is to name a line without explaining its role. Memory cue: for line questions, write type plus visual effect, such as diagonal plus movement.