To avoid damaging the x-ray tube components, the electrical power supplied to the x-ray tube must be:

The correct choice emphasizes the necessity of using direct current (DC) to power the x-ray tube, which is crucial for preventing damage to its components. X-ray tubes are designed to operate with a steady and unidirectional flow of electric current. This minimizes fluctuations that could lead to issues such as overheating or undesirable wear and tear on the tube's anode and cathode.

Using direct current ensures that the electrons flow consistently from the cathode to the anode during x-ray production. This steady flow is vital for maintaining the integrity of the x-ray tube while producing high-quality images. If alternating current (AC) were used, the directional flow of electricity would change constantly, putting significant strain on the components and potentially damaging them. Additionally, high voltage is necessary for the operation of the x-ray tube, but without proper current type, it can lead to severe technical failures.

The other options either focus on power specifications not suited for x-ray tube functionality or endorse types of electricity that could lead to detrimental effects on tube longevity. Thus, employing direct current aligns with the operational requirements of x-ray tubes, making it the optimal choice for maintaining their integrity and extending their lifespan.