Under what circumstances is a transponder required while flying from Alice Airport to McCampbell Airport at 5,500 feet MSL?

A transponder is required when overflying the Corpus Christi Class C airspace, which is a specific regulatory requirement for aircraft operating within or in proximity to controlled airspace. Class C airspace typically has established dimensions that require pilots to maintain specific communication and surveillance protocols. In this case, as the flight route from Alice Airport to McCampbell Airport involves passing through this airspace, having a transponder becomes necessary for maintaining situational awareness and ensuring proper separation from other air traffic.

While it's true that transponders are commonly required for flights in controlled airspace or above certain altitudes, this particular scenario references the specific operational requirement related to the Class C airspace over Corpus Christi, making this answer correct in the context of compliance with air traffic regulations.

The other options do not fully capture the specific requirement related to the Class C airspace or misinterpret the general rules concerning transponder use. For instance, simply stating that a transponder is not required ignores the regulations about flying in controlled airspaces, while the notion of needing one when leaving or entering alert areas doesn’t align with the fundamental requirements of controlled airspace operations. Additionally, just stating that a transponder is required during all flights above 5,000 feet does not take