Which cue is most useful while sketching glass?

Correct answer: Selected edges, reflections, and refraction

Glass is transparent, so its form is communicated through selective visual cues rather than a uniformly filled tone. Bright or dark edges, broken reflections, and changes caused by refraction reveal its shape and thickness. Option D is correct. A solid black fill makes glass opaque, a thick outline alone gives insufficient volume, and leaving every area white removes the useful contrast needed to show transparency.