Final answer:
The CR/DR systems' dynamic range is wide and captures low to high-density information, but the exact line representing this in Figure 4-2 cannot be determined without the visual context of that figure.
Step-by-step explanation:
The student has asked which line represents the dynamic range offered by computed radiography/digital radiography (CR/DR). Unfortunately, without the visual context of Figure 4-2, we cannot definitively answer which line (A or B) indicates the dynamic range of CR/DR. However, it is important to note that CR/DR systems have a wide dynamic range, capable of capturing both very low and very high-density information, which is one of the advantages over conventional film-based radiography. This wide dynamic range allows for greater detail in the imaging of various tissue densities. It can be inferred from the provided information that the line representing CR/DR would likely be an increasing line, probably illustrating the expanding range of intensities that CR/DR systems can detect and represent in their imaging.