Which scope consists of a rectangular scanned field made of parallel vertical trace lines?

The B-scope is designed to display a rectangular scanned field using parallel vertical trace lines. This type of scope is particularly useful in radar systems, as it provides a two-dimensional representation of the targets in the scanned area. By utilizing vertical lines to represent radial distances, the B-scope effectively conveys information about the range and azimuth of targets within its field of view.

In contrast, other types of scopes serve different purposes and display data differently. The PPI (Plan Position Indicator) scope typically uses a circular format to represent targets with the origin located at the center, while the A-scope presents information in a linear fashion, showing amplitude versus time along a single line. The RHI (Range Height Indicator) scope offers a vertical presentation that helps visualize targets in terms of their height and distance away, which is distinct from the rectangular representation of the B-scope.

Choosing the B-scope indicates a clear understanding of the display's unique format and its application in radar technology, making it the appropriate answer for this question.