Final answer:
A private pilot may not be paid for the operating expenses of a flight but can share the operating expenses, such as fuel and airport fees, with passengers. They must pay at least their pro-rata share and cannot earn compensation for their services. Thus (option b) is right answer.
Step-by-step explanation:
According to regulations pertaining to privileges and limitations, a private pilot may not be paid for the operating expenses of a flight. Option (b) is correct: a private pilot may not pay less than the pro-rata share of the operating expenses of a flight with passengers, provided the expenses involve only fuel, oil, airport expenditures, or rental fees.
As such, private pilots cannot earn compensation for flying; rather, they can only share the actual expenses with their passengers. It is important for pilots to understand these regulations to ensure they operate within the bounds of the law and maintain the amateur status of their private license.
The reasoning behind these rules, similar to the rule featured in the question's prompt regarding Air Force height requirements, is to ensure a level playing field and adhere to specific standards set for different circumstances.