Which cue can be more important than rough texture to show an object as glass?

Correct answer: Transparency and shiny highlight

Direct answer: A is correct. Glass is usually recognised through the way it allows light to pass through or reveal what lies behind it, together with sharp or bright reflections and highlights. These optical cues can communicate glass more effectively than a rough surface pattern. The artist does not need to make glass look grainy; its surface is commonly shown through transparency, reflected light, selective edges, and highlights. B is wrong because grainy roughness suggests a rough material rather than a smooth glass surface. C is wrong because thick black outlines alone do not show transparency or the behaviour of light. D is wrong because completely flat colour removes the changes in light that help identify glass. Memory cue: for glass, observe what light passes through and what light reflects.