Final answer:
The light and dark regions observed in a double-slit experiment are referred to as maxima and minima, corresponding to areas of constructive and destructive interference, respectively.
Step-by-step explanation:
In the context of a double-slit experiment, the regions on the screen where constructive interference occurs, resulting in higher light intensity, are known as maxima. Conversely, the regions where destructive interference occurs, leading to little to no light and thus lower intensity, are termed minima. These patterns are a result of the principles of wave interference, where waves that are in phase reinforce each other to form maxima, and waves that are out of phase cancel each other to form minima.
In conclusion, the correct term for the light and dark regions observed on a screen in a double-slit experiment is b) Maxima and minima.