Final answer:
Temporary flight permits are often issued for a specific trip or a short duration, typically less than 12 months, depending on the country's aviation regulations.
Step-by-step explanation:
The duration for which temporary flight permits are issued can vary depending on the regulations of the specific aviation authority of a country or region. These permits are typically issued for aircraft that may not meet the standard airworthiness requirements but need to fly for specific purposes such as delivery, maintenance, testing, or emergencies. In the context of the United States, for example, the Federal Aviation Administration (FAA) issues special flight permits, which can be temporary and are often valid for a trip or a specified amount of time that is commonly less than 12 months.
However, since the duration can vary by country and the specific situation of the aircraft, it's important to consult the relevant aviation authority to get the exact period for which a temporary flight permit is issued. To answer the quiz-style question, if none of the other options are less than 12 months, the closest correct choice would be A. 12 months or less, although for precise information, one should always refer to the specific regulations that apply.