Final answer:
Increasing filtration decreases the scale of contrast as it removes low-energy photons from the X-ray beam, reducing the differences in tissue densities in the resulting image. Option B is correct.
Step-by-step explanation:
When increasing filtration, the scale of contrast typically decreases. This outcome occurs because filtration tends to remove low-energy photons from the X-ray beam, which are responsible for creating contrast in the resulting image.
Without these lower-energy photons, the differences between tissues of slightly different densities become less apparent, leading to a reduction in contrast. In radiologic terms, this means we would observe a longer or 'grayer' scale of contrast. Thus, the correct answer is B) Decreases the scale.