Final answer:
An interference pattern is formed due to diffraction, which is a wave behavior of light. Light beams spread out due to diffraction, and if double slits were closer together, the bands in a diffraction pattern would be farther apart.
So The Correct Option is; b) Diffraction.
Step-by-step explanation:
The behavior of light indicated by an interference pattern is diffraction. When light passes through a double slit, it creates a characteristic pattern of bright and dark bands known as an interference pattern, which is a result of the wave nature of light.
Indeed, diffraction demonstrates the wave behavior of light, as shown when waves overlap and either reinforce or cancel each other out, leading to the bright and dark bands in an interference pattern.
For example, in Figure 21.14 depicting light through a double slit, the interference pattern is analogous to that of water waves, showcasing the wave property of light.
Similarly, when discussing beams of light and why they eventually spread out, it is due to the light being always diffracted, which means it naturally spreads as it travels.
If the slits were to be brought closer together, the spacing of the bands in the diffraction pattern would spread farther apart, as indicated in a short answer under the heading Understanding Diffraction and Interference.