Which of the following best describes a seaplane?

A seaplane is specifically designed to take off from and land on water, which is why it is equipped with floats or a hull that allows it to maneuver efficiently on aquatic surfaces. This characteristic distinguishes seaplanes from other kinds of aircraft that are primarily built for operation on land, such as traditional airplanes. The design of a seaplane enables it to be used in various applications, including transportation, rescue missions, and access to remote locations that may lack traditional runways.

While the other options touch on different aspects of aviation, they do not accurately capture the primary function and design of a seaplane. An aircraft designed to maneuver on land lacks the specialized features needed to operate on water, and an aircraft used exclusively for aerial tours does not encompass the broader capabilities of a seaplane. Furthermore, the idea that a seaplane cannot carry passengers is incorrect, as many seaplanes are indeed built to transport passengers safely and comfortably. Hence, the defining feature of a seaplane is its ability to operate on water, making the chosen answer the most accurate.