Final answer:
The correct option is Supersonic.
Speeds of Mach 1.2 to Mach 5.0 fall into the supersonic category, which includes speeds exceeding the speed of sound and can cause a sonic boom.
Step-by-step explanation:
Speeds of Mach 1.2 to Mach 5.0 are classified as supersonic. This term is used to describe speeds that exceed the speed of sound. When a jet or any object travels at such speeds, it can cause a sonic boom, a loud and distinctive sound resulting from the shock waves created by an object moving through the air faster than the speed of sound. Sonic booms can be heard when a supersonic aircraft is flying overhead, even if the aircraft itself might not be visible due to its high speed and altitude.
Example:
A jet flying at an altitude of 8.50 km reaches a speed of Mach 2.00. Given that the speed of sound is 340.00 m/s, the time it would take for a sonic boom to reach a stationary observer after the jet is directly overhead can be calculated using the properties of sound propagation and the geometry of the situation.