What must a sport pilot do to carry passengers?

To carry passengers, a sport pilot is required to make three takeoffs and landings within the last 90 days. This requirement ensures that the pilot maintains a level of proficiency and recent experience that is crucial for the safety of flight operations, especially when flying with passengers on board.

This rule is part of the broader aviation safety regulations that aim to ensure that pilots are adequately practiced and familiar with their aircraft. The specific time frame of 90 days establishes a reasonable limit for the currency of these maneuvers, reflecting the need for pilots to regularly engage with practical flying skills.

The other choices would not fulfill the regulatory requirements for carrying passengers. For example, making three takeoffs and landings in the last 30 days does not meet the 90-day stipulation, a special passenger carrying endorsement is not necessary for sport pilots, and completing a night flying review is unrelated to carrying passengers during daytime flights. Therefore, option B accurately captures the requirement set forth for sport pilots wishing to take passengers.