At what point should turbojets cross when cleared at JAN ATCT?

The correct choice indicates that turbojets should cross at 31 miles east of Monroe (MLU) at an altitude of 13,000 feet when cleared by the Jackson ATCT (JAN ATC). The reason for this specific altitude is likely related to the air traffic management procedures established to ensure safe separation between aircraft while maintaining optimal traffic flow.

Crossing at 13,000 feet strikes a balance between sufficient altitude for turbojet operations and consideration for other aircraft that may be operating at lower altitudes in the vicinity. By specifying this altitude, air traffic control ensures that turbojets can safely navigate without interfering with procedural airspace or other aircraft operating within the same region.

Altitude restrictions like the one indicated are typically decided based on a variety of factors, including terrain, other flight operations, and standard procedural requirements established for airspace in that area. Therefore, the choice of 13,000 feet ensures that turbojets can execute effective climb-out procedures while remaining safely separated from other traffic, adhering to safety regulations and procedures in place.