A shade between black and white?

• A. Legend
• B. Halftone
• C. Isopleths
• D. Hydrography

Answer: (B)

In cartography, representing gray tones on a map is done with halftone shading. Halftone uses a pattern of tiny dots whose size and spacing create the illusion of intermediate tones between black and white. This lets a map show varying densities or features without using full color. The other terms refer to different map aspects: a legend is the key that explains symbols, isopleths are lines that connect equal values (like contour lines), and hydrography deals with mapping bodies of water. So halftone is the method that best describes a shade between black and white.