Information:  - Marshal of Italy Armando Diaz , 1st Duke of the Victory , OSSA , OSML , OMS , OCI ( 5 December 1861 -- 28 February 1928 ) was an Italian General and a Marshal of Italy .  - The Italian Royal Air Force (Regia Aeronautica Italiana) was the name of the air force of the Kingdom of Italy. It was established as a service independent of the Royal Italian Army from 1923 until 1946. In 1946, the monarchy was abolished and the Kingdom of Italy became the Italian Republic, whereupon the name of the air force changed to Aeronautica Militare Italiana.  - Marshal of Italy Luigi Cadorna, (4 September 1850  21 December 1928) was an Italian General and Marshal of Italy, most famous for being the Chief of Staff of the Italian Army during the first part of World War I.  - Marshal of the air force is the English term for the most senior rank in a number of air forces. The ranks described by this term can properly be considered marshal ranks.  - Marshal of Italy (Italian: "Maresciallo d'Italia") was a rank in the Italian Royal Army ("Regio Esercito"). Originally created in 1924 by Italian dictator Benito Mussolini for the purpose of honoring Generals Luigi Cadorna and Armando Diaz, the rank was granted to several other general officers from 1926 to 1943. The rank was the highest in the Italian Army prior to the creation of the rank of First Marshal of the Empire in 1938. The rank of Marshal of Italy was abolished in 1946 with the creation of the Republic of Italy. The equivalent Royal Navy ("Regia Marina") rank was Grand Admiral ("Grande Ammiraglio"), while the equivalent Air Force ("Regia Aeronautica") rank was Marshal of the Air Force ("Maresciallo dell'Aria"), all of them abolished for the Armed Forces of the Republic of Italy.  - The Royal Navy (Italian: Regia Marina) was the navy of the Kingdom of Italy ("Regno d'Italia") from 1861 to 1946. In 1946, with the birth of the Italian Republic ("Repubblica Italiana"), the Royal Navy changed its name to Military Navy ("Marina Militare").    After reading the paragraphs above, choose the best answer for the entity that related to 'armando diaz' with the relationship of 'military branch'.  Choices: - air force  - army  - italian army  - navy  - regia aeronautica  - royal air force
The answer to this question is:
regia aeronautica