ISO 100 speed film can normally be expected to be correctable for which of the following?

ISO 100 speed film has a moderate sensitivity to light, which allows for some latitude in exposure mistakes. Correcting for overexposure and underexposure within certain limits is key to preserving image quality and detail.

When you have overexposure, the film can retain detail in highlights even if it is exposed more than the ideal setting. Two stops overexposure means the film still captures a usable image, albeit potentially with some loss of highlight detail. This can be corrected in post-processing if the overexposure is not excessive, making it possible to adjust by two stops.

On the other hand, if the film is underexposed by one stop, there's still appropriate detail and tonal range captured that can be adjusted later. Therefore, a combination of two stops overexposure and one stop underexposure makes the correct answer because it reflects the film's ability to handle exposure variations effectively, allowing photographers some flexibility while shooting.

This capability is important for many photographic scenarios, where lighting conditions can be unpredictable and rapid adjustments might be necessary.