Only the Brave is a 2006 independent film about the 100th Infantry Battalion/442nd Regimental Combat Team, a segregated World War II fighting unit primarily made up of "Nisei" Japanese Americans, which for its size and length of service became the most decorated unit in U.S. military history.
 The film, produced and directed by Lane Nishikawa is a fictionalized account of the rescue of the Lost Battalion.
The 100th Infantry Battalion is the only infantry unit in the United States Army Reserve.
 In World War II, the then-primarily Nisei battalion was composed largely of former members of the Hawaii Army National Guard.
 The 100th saw heavy combat during World War II before and after combining with the 442nd Infantry Regiment, another mostly Nisei military unit, into a single fighting combat team.
 Based at Fort Shafter, Honolulu, Hawaii, the 100th Battalion has reservists from Hawaii, American Samoa, Guam and Saipan, and has deployed to Iraq and Kuwait.
 The unit was unofficially nicknamed the "Purple Heart Battalion", with the motto "Remember Pearl Harbor".
Regiment Northern Transvaal is a reserve mechanised infantry unit of the South African Army.
 As a reserve unit, it has a status roughly equivalent to that of a British Army Reserve or United States Army National Guard unit.
The Army Reserve (previously known as the Territorial Force, Territorial Army (TA) and the Territorial and Army Volunteer Reserve (TAVR) from 1920 to 2014) is the active-duty volunteer reserve force and integrated element of the British Army.
 The Army Reserve was created as the Territorial Force in 1908 by the Secretary of State for War, Richard Haldane, when the Territorial and Reserve Forces Act 1907 combined the previously civilian-administered Volunteer Force, with the mounted Yeomanry (at the same time the Militia was renamed the Special Reserve).
 Most Volunteer infantry units had unique identities, but lost these in the reorganisation, becoming Territorial battalions of Regular Army infantry regiments.
 Only one infantry unit, the London Regiment, has maintained a separate identity.
The Artists Rifles is a regiment of the British Army Reserve.
 Raised in London in 1859 as a volunteer light infantry unit, the regiment saw active service during the Second Boer War and World War I, earning a number of battle honours.
 It did not serve outside Britain during World War II, as it was used as an officer training unit at that time.
 The regiment was disbanded in 1945, but in 1947 it was re-established to resurrect the Special Air Service Regiment.
 Today, the full title of the Regiment is 21 Special Air Service Regiment (Artists) (Reserve) (21 SAS(R)) and with 23 Special Air Service Regiment (Reserve) (23 SAS(R)), it forms the Special Air Service (Reserve) (SAS(R)).
The Natal Carbineers Regiment is an infantry unit of the South African Army.
 As a reserve unit, it has a status roughly equivalent to that of a British Army Reserve or United States Army National Guard unit.
The 108th Training Command (Initial Entry Training) is a United States Army Reserve unit headquartered in Charlotte, North Carolina.
 At its activation, the unit was designated as the 108th Airborne Division, but in 1952 was redesignated the 108th Infantry Division.
 In 1956, the division was again reorganized, this time to the designation as the 108th Division (Institutional Training).
 Under the U.S. Army Reserve Transformation of 2005, the 108th was reorganized to is current structure as the 108th Training Command (Initial Entry Training (IET)).
 The command is currently one of the largest in the Army Reserve, commanding and coordinating 9,000 soldiers.
The 202nd QC Ready Reserve Battalion, 1502nd Infantry Brigade (Ready Reserve), known officially as The Second to None 202nd, is one of the battalions of the Philippine Army Reserve Command, which is organic to the 1502nd Quezon City Ready Reserve Brigade.
 It is an infantry unit, and specializes in MOUT, disaster relief, and Civil Military Operations.
Regiment Paul Kruger is a West Rand infantry unit named after former Zuid Afrikaanse Republik President, Paul Kruger, for whom the nearby city of Krugersdorp is also named.
 Regiment Paul Kruger is a Motorised Infantry regiment of the South African Army.
 As a reserve unit, it has a status roughly equivalent to that of a British Army Reserve or United States Army National Guard unit.
The 201st Infantry Battalion (Ready Reserve), 1502nd Infantry Brigade (Ready Reserve), known officially as The Proud 201st, is one of the battalions of the Army Reserve Command which is organic to the 1502nd Infantry Brigade (Ready Reserve).
 It is an infantry unit, and specializes in MOUT, disaster relief, and Civil Military Operations.

Question: The only infantry unit in the United States Army Reserve was the subject of what 2006 film?
Answer: Only the Brave