Which of the following best explains why airline capacity is mostly fixed? Group of answer choices A. Limited infrastructure: Airports and airspace have finite capacity, constraining the number of flights that can operate simultaneously. B. Regulatory restrictions: Government regulations impose limits on the number of flights airlines can operate, often to manage air traffic and safety. C. Fleet constraints: Airlines have a fixed number of aircraft in their fleet, and expanding it requires significant investment and time. D. Seasonal demand: Airline capacity is adjusted seasonally to match fluctuations in demand, resulting in a relatively fixed overall capacity throughout the year