Which line can clearly show the structure of an iron grill?

Correct answer: Regular geometric and straight lines

Correct answer: A. An iron grill is built from repeated bars or wires arranged in a definite framework. Regular straight and geometric lines can show its vertical and horizontal members, spacing, intersections, and overall structure clearly. A is correct because the selected line quality matches both the manufactured form and the organized construction of the grill. B is wrong because soft cloud-like lines suggest a fluffy or changing surface, not rigid metal bars. C is wrong because irregular water ripples suggest flowing movement rather than a fixed framework. D is wrong because a blurred line hides edges and intersections, making the structure difficult to read. The artist may add shading or texture later, but the structural drawing begins with clear, controlled lines. Memory cue: rigid structure needs clear geometry; flowing material needs softer variation.