Final answer:
To prevent shape distortion, the object and the image receptor must be parallel. Proper alignment ensures a true representation of the object's shape, while any misalignment can cause stretching or compression in the resulting image.
Step-by-step explanation:
To prevent shape distortion in imaging (like in radiography, photography, or optical systems), two elements must be parallel: B. The object and the image receptor. Ensuring that the object (the subject of the imaging) is parallel to the image receptor (such as a photographic film, a digital sensor, or an imaging screen) helps maintain the object's proportions and prevents distortion. By keeping these components aligned, the resulting image is a true representation of the object's shape. Distortion occurs when there is a misalignment, leading to parts of the image appearing stretched or compressed in relation to other parts.
In the context of mirrors or lenses, it's also important to consider the central ray (CR), but its relationship to parallelism is more about ensuring correct angles of incidence and reflection rather than preventing shape distortion.