Look at the table of densities below. Identify one material which will float MATERIAL Density (g/cm3) at 20oC
Acrylic 1.18
Aluminum 2.73
Brass 8.55
Wood 0.40
Copper 8.90
Gold 19.3
Iron 7.68
Lead 11.4
Marble Chips 2.70
Nylon 1.30
Rubber 1.51
Graphite 2.16
Steel 7.85
Water 0.99

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

it's c (engineer's do their work with mechanical stuff not on any living being)