Which aircraft is designed for unmanned aerial operations and is classified as a UAV?

The MQ-8B Fire Scout is the correct answer because it is specifically designed for unmanned aerial operations and classified as an Unmanned Aerial Vehicle (UAV). This rotary-wing UAV is used by the Navy for reconnaissance, surveillance, and target acquisition missions, demonstrating its capability to operate without a human pilot on board. Its advanced systems allow it to fly autonomously or be remotely controlled, making it suitable for military operations where personnel safety is a concern and for gathering intelligence in a variety of operational environments.

The other choices represent manned aircraft or different types of vehicles not classified as UAVs. The OT-1B Otter is a light utility aircraft, the P-8A Poseidon is a maritime patrol aircraft with a crew, and the T-39/D/N/G Sabreliner is a business jet used primarily for training in the Navy, all of which involved human pilots.