Contours are imaginary lines on a map that connect points of equal value for a particular variable. In this case, the correct answer is option 3, which states that contours represent places of equal altitudes. Contour lines on a topographic map indicate areas of the same elevation or height above sea level. These lines will create a unique pattern that reflects the shape of the land. Areas of higher elevation are represented by closely spaced contour lines, while areas of lower elevation have contours that are more widely spaced. Contours are essential for understanding the shape of the land and are frequently used in geography, navigation, and land surveying.