Final answer:
A wave is a disturbance that propagates from its point of origin, carrying energy without mass. Mechanical waves need a medium, unlike electromagnetic waves. Pulse waves are single disturbances that travel at a consistent speed.
Step-by-step explanation:
The best description of a wave is b. A wave is a disturbance that propagates from the place where it was created. Waves are disturbances that move through a medium, carrying energy without transferring mass. They can be mechanical, requiring a medium to travel through, like sound and water waves, or electromagnetic, which do not require a medium and can travel through a vacuum, like light waves. An example of a wave that people can observe is when you shake the end of a rope, the energy travels from your hand to the other end of the rope while the rope itself doesn't move along with the energy.
Pulse waves are instances of waves consisting of single or few disturbances that maintain their shape and propagate through the medium at a constant speed. Waves are often periodic, meaning they repeat for several cycles and are associated with simple harmonic motion such as the fans doing the wave in a stadium, where the disturbance travels around the stadium but the fans remain mostly in their seats.