Answer the following question given this paragraph: 

The modern day formulation of gun powder is called black powder. It is still commonly used today. Its formulation is still quite similar to what was used in 9 th century China. Black powder is considered a low explosive. It is a mixture that burns quickly, but the resulting shock wave travels at subsonic speeds. The speed at which it burns is dependent on the accessibility of oxygen atoms to the carbon source. In contrast, high explosives like nitroglycerin detonate instead of burning, creating shock waves that are supersonic (faster than the speed of sound).


Q: High explosives create shock waves that exceed the speed of sound, a phenomenon that goes by what term?

 Choices:

- light speed

- ion speed

- turbulence

- supersonic

A:
supersonic
