Air transport is generally faster than ground transport for long distances, but the exact distance depends on various factors. For distances greater than 45 nautical miles, air transport is likely to be faster.
The correct answer to the given question is option c.
In general, air transport is faster than ground transport for long distances. However, the exact distance at which air transport becomes faster depends on various factors such as the speed of the vehicles, traffic conditions, and the efficiency of the transportation system.
For example, for shorter distances like 30 or 45 nautical miles, ground transport may be faster if there are limited delays and the speed of the car or train is relatively high. On the other hand, for longer distances like 75 or 100 nautical miles, air transport is usually faster due to its higher speed and avoidance of traffic congestion.
Therefore, in the given options, the correct answer would be (c) 45 nautical miles, as that would be the minimum distance where air transport is likely to be faster than ground transport.