Final answer:
The correct answer is (b) quantum mottle, which is due to the statistical nature of photon distribution when there is an insufficient quantity of photons, resulting in a grainy image on the film.
Step-by-step explanation:
When an insufficient quantity of photons strikes the intensifying screen, quantum mottle will appear on the film as graininess. Therefore, the correct answer to the question is (b) quantum mottle.
Quantum mottle is caused by the statistical nature of the photon distribution on the screen. When there aren't enough photons hitting the screen, the resulting image can have a mottled or grainy appearance due to this distribution, making the image less clear. This concept is associated with the fundamental properties of photons having quantized energy and momentum, and the interference patterns they create, which can be thought of as akin to wave properties as well as particle properties.