The correct answer is B) a straight line drawn on the chart approximates a great circle. In a Lambert conformal projection, which is commonly used for navigational charts, a straight line drawn on the chart represents an approximation of a great circle. This is because the projection is designed to preserve the shapes and angles of features on the chart, even at high latitudes. As a result, a straight line on the chart will closely match the shortest distance between two points, which is a great circle route. The other options are incorrect because: A) the course angle is measured relative to the meridians, not the mid-longitude; C) the chart can be used outside the standard parallels, although the distortion may increase; and D) distances can be measured directly from the chart, though they may not be exact due to the nature of the projection.