Given the task definition and input, reply with output. In this task, you are given a text which is the body of a document. You are given a question and options. Pick the correct number. Don't generate anything else apart from the numbers provided in options.

Context: The Heinkel Doppeldecker 43 was a prototype German fighter aircraft of the 1930s. A single-engined single-seat biplane the HD 43 was designed to meet a secret German Reichswehr requirement for a single seat fighter. It had two-bay wooden wings with a steel-tube fuselage and was powered by a 750 hp (600 kW) BMW VI engine. The single prototype flew in 1931.It was evaluated against the Arado Ar 65 with the Arado being selected and no production of the Heinkel followed.
Question: The document can be classified to which topic?
Options: 1)Film, 2)Animal, 3)WrittenWork, 4)MeanOfTransportation, 5)Athlete
4