Which of the following is a requirement for carrying passengers as a commercial pilot?

To carry passengers as a commercial pilot, a fundamental requirement is that you must have completed three takeoffs and three landings in the same category and class of aircraft you plan to operate, within the preceding 90 days. This ensures that the pilot maintains proficiency and is familiar with the handling characteristics of the aircraft. The three takeoffs and landings must be in conditions that resemble the types of operations expected during the flight with passengers aboard.

The other options do not directly address the specific regulatory requirement for carrying passengers. For instance, obtaining a new aircraft type rating would be necessary when transitioning to a different aircraft type, but it is not a general prerequisite for carrying passengers. Logging 50 hours of solo flight pertains to the training requirements for a pilot certificate rather than a passenger-carrying requirement, and although flying cross-country flights can enhance skills, it is not a specific regulatory requirement for carrying passengers.