Which of these describes a wave being reflected?

The wave encounters some change in medium. The wave moves through the new medium in a different direction, but at an equal angle at which it hit the surface.
Two waves move towards each other and the crest of each wave overlaps, creating a new wave that has a greater amplitude than either individual wave.
The wave encounters some corner or a small opening. The wave bends and fans out, forming an arc.
The wave encounters some obstacle or change in medium. The wave bounces off the surface and moves in a different direction, but at an angle equal to the one at which it hit the surface.