Final answer:
An example of a longitudinal wave is hitting a slinky at one end, where the coils move parallel to the wave's direction, making option B the correct answer.
Step-by-step explanation:
The question asks to identify an example of a longitudinal wave. Longitudinal waves are waves where the particle displacement is parallel to the direction of wave propagation. An example of this kind of wave is when you hit a slinky at one end; the coils of the slinky push and pull along the same direction as the wave travels, forming compressions and rarefactions. Therefore, the answer is B. Hitting a slinky at one end.
It's important to distinguish this from other types of waves. For instance, water waves and ripples on a pond (options A and C) are often a combination of transverse and longitudinal wave motions. Microwaves (option D), being a form of electromagnetic radiation, are examples of transverse waves, not longitudinal.