Which variables can be measured in a B-scan?

A B-scan, which is a form of ultrasound imaging, primarily measures variables that relate to the spatial dimensions and positioning of objects. Among the options provided, the reason why the first choice stands out is because it includes variables that directly relate to how targets are located and characterized in a 3-dimensional space.

The range refers to the distance of the target from the radar system, while azimuth indicates the angular position of the target relative to a designated reference line, typically the north. Intelligence received by RADAR encompasses the information obtained about the target's characteristics, which is essential for interpretation of the gathered data.

In contrast, the other choices focus on aspects that do not directly apply to B-scan measurements. For instance, altitude, speed, and direction pertain more to a navigational context rather than the specifics of B-scan imagery. Frequency, amplitude, and phase are terms that relate to signal processing rather than imaging. Lastly, signal strength, clarity, and resolution generally connect to the overall quality of an image or signal but do not encapsulate the specific spatial dimensions necessary for a B-scan's interpretation. Thus, the first choice accurately reflects the measurements relevant to B-scan imaging.