Final answer:
The correct answer is B) Class E airspace, which extends from the surface up to 14,999 feet Above Ground Level.
Step-by-step explanation:
The question relates to the specifications of a low-level air route. A low-level air route is an area of controlled airspace assigned for the transit of aircraft at lower altitudes. The correct answer to the question is: A low-level air route is Class E airspace and extends from the surface up to below 18,000 feet AGL (Above Ground Level).
Thus, the complete statement should be: A low-level air route is B) E, the surface up to 14,999 AGL.
In general, the Federal Aviation Administration regulates these airspaces and sets specific separation standards between aircraft to ensure their safety, similar to the way that quantum mechanics provides rules for the positions and energy levels of electrons within an atom.