Final answer:
To produce high subject contrast in an x-ray image, all three actions of x-rays (penetration, absorption, and scattering) are necessary.
Step-by-step explanation:
When x-rays pass through a patient, all three actions can occur: they can penetrate, get absorbed, and scatter.
X-rays penetrate the body and can pass through different tissues and organs, depending on their density. Dense materials like bones absorb more x-rays, resulting in darker areas on the x-ray image. X-rays also scatter when they interact with electrons in the body's tissues, which can affect the image quality.
Therefore, to produce high subject contrast in an x-ray image, all three actions of x-rays (penetration, absorption, and scattering) are necessary. This option is represented by choice D. 1, 2 & 3.