The correct answer is option 1: supersonic.
The Mach number is a dimensionless quantity that represents the ratio of the speed of an object to the speed of sound in a medium. When the Mach number is greater than 1, it means that the object is traveling faster than the speed of sound in that medium.
In aerodynamics, the speed of sound is dependent on various factors such as temperature, pressure, and density of the medium. In air at sea level, the speed of sound is approximately 343 meters per second. Therefore, if a body has a Mach number greater than 1, it means that it is traveling faster than 343 meters per second in air at sea level.
When an object is traveling at such high speeds, it is said to be supersonic. In this case, the body is moving faster than the speed at which the pressure waves (sound waves) propagate in the medium. This can lead to several interesting phenomena, such as shock waves and sonic booms.
Therefore, if a body has a Mach number greater than 1, it is considered supersonic, and option 1 is the correct answer.