Concept:Mass shading requires a soft pencil that can produce smooth, dark tones.Explanation:H and 2H pencils are hard pencils, so they produce light and fine lines, which are not ideal for mass shading.B and 2B pencils are soft pencils, so they produce darker and broader strokes suitable for shading.Between B and 2B, the 2B pencil is softer and therefore more appropriate for rendering masses of tone on a drawing.Answer:D. 2B