Question: Western Allied invasion of Germany and Operation Undertone, occurred during which event?

Context paragraphs:
Operation Dragoon: Operation Dragoon (initially Operation Anvil) was the code name for the Allied invasion of Southern France on 15August 1944.  The operation was initially planned to be executed in conjunction with Operation Overlord, the Allied landing in the Normandy, but the lack of available resources led to a cancellation of the second landing.  By July 1944 the landing was reconsidered, as the clogged-up ports in Normandy did not have the capacity to adequately supply the Allied forces.  Concurrently, the French High Command pushed for a revival of the operation that would include large numbers of French troops.  As a result, the operation was finally approved in July to be executed in August.

Operation Citadel: Operation Citadel (German: "Unternehmen Zitadelle" ) was a German offensive operation against Soviet forces in the Kursk salient during the Second World War on the Eastern Front that initiated the Battle of Kursk.  The deliberate defensive operation that the Soviets implemented to repel the German offensive is referred to as the Kursk Strategic Defensive Operation.  The German offensive was countered by two Soviet counter-offensives, Operation Polkovodets Rumyantsev (Russian: Полководец Румянцев ) and Operation Kutuzov (Russian: Кутузов ).  For the Germans, the battle was the final strategic offensive that they were able to launch on the Eastern Front.  As the Allied invasion of Sicily began Adolf Hitler was forced to divert troops training in France to meet the Allied threats in the Mediterranean, rather than use them as a strategic reserve for the Eastern Front.  Germany's extensive loss of men and tanks ensured that the victorious Soviet Red Army enjoyed the strategic initiative for the remainder of the war.

Operation Corkscrew: Operation Corkscrew was the code name for the Allied invasion of the Italian island of Pantelleria (between Sicily and Tunisia) on 11 June 1943, prior to the Allied invasion of Sicily during the Second World War.  There had been an early plan to occupy the island in late 1940 (Operation Workshop), but this was aborted when the Luftwaffe strengthened the Axis air threat in the region.

Arthur Tedder, 1st Baron Tedder: Marshal of the Royal Air Force Arthur William Tedder, 1st Baron Tedder, {'1': ", '2': ", '3': ", '4': "} (11 July 1890 – 3 June 1967) was a senior Royal Air Force commander.  He was a pilot and squadron commander in the Royal Flying Corps in the First World War and he went on to serve as a senior officer in the Royal Air Force during the inter-war years when he served in Turkey, Great Britain and the Far East.  During the Second World War, as Air Officer Commanding RAF Middle East Command, Tedder directed air operations in the Mediterranean and North Africa, including the evacuation of Crete and "Operation Crusader" in North Africa.  His bombing tactics became known as the "Tedder Carpet".  Later in the war Tedder took command of Mediterranean Air Command and in that role was closely involved in the planning of the Allied invasion of Sicily and then the Allied invasion of Italy.  When Operation Overlord—the invasion of France—came to be planned, Tedder was appointed Deputy Supreme Commander at Supreme Headquarters Allied Expeditionary Force under General Eisenhower.  After the war he served as Chief of the Air Staff, in which role he advocated increased recruiting in the face of many airmen leaving the service, doubled the size of RAF Fighter Command and implemented arrangements for the Berlin Airlift in 1948.  After the war he held senior positions in business and academia.

Western Allied invasion of Germany: The Western Allied invasion of Germany was coordinated by the Western Allies during the final months of hostilities in the European theatre of World War II.  The Allied invasion of Germany started with the Western Allies crossing the Rhine River in March 1945 before fanning out and overrunning all of western Germany from the Baltic in the north to Austria in the south before the Germans surrendered on 8 May 1945.  This is known as the "Central Europe Campaign" in United States military histories.

The Man Who Never Was (book): The Man Who Never Was is a 1953 book by Ewen Montagu about the World War II Operation Mincemeat.  Montagu played a leading role in the 1943 scheme to deceive the Germans about the planned Allied invasion of Sicily.  Montagu's work formed the basis for a 1956 film by the same title.  The scheme entailed releasing a dead body just off the coast of Spain, where strong currents caused it to drift ashore in an area where a skilled German secret agent was known to operate.  The corpse was to appear to be the victim of an airplane crash, the non-existent Royal Marine Major William Martin, who had letters in a briefcase that hint at a forthcoming Allied invasion of Greece and Sardinia, rather than the obvious target of Sicily.

Matthew Ridgway: General Matthew Bunker Ridgway (March 3, 1895 – July 26, 1993) was the 19 Chief of Staff of the United States Army.  He served with great distinction during World War II, where he was the Commanding General (CG) of the 82nd Airborne Division, leading it in action in Sicily, Italy and Normandy, before taking command of the newly formed XVIII Airborne Corps in August 1944, holding this post until the end of the war, commanding it in the Battle of the Bulge, Operation Varsity and the Western Allied invasion of Germany.

Allied invasion of Italy: The Allied invasion of Italy was the Allied amphibious landing on mainland Italy that took place on 3 September 1943 during the early stages of the Italian Campaign of World War II.  The operation was undertaken by General Sir Harold Alexander's 15th Army Group (comprising General Mark W. Clark and General Bernard Montgomery's British Eighth Army) and followed the successful invasion of Sicily.  The main invasion force landed around Salerno on 9 September on the western coast in Operation Avalanche, while two supporting operations took place in Calabria (Operation Baytown) and Taranto (Operation Slapstick).

Operation Undertone: Operation Undertone was a large assault by the U.S. Seventh and French 1st Armies of the U.S. Sixth Army Group as part of the Allied invasion of Germany in March 1945 during World War II.

21st Army Group: The 21st Army Group was a World War II British headquarters formation, in command of two field armies and other supporting units, consisting primarily of the British Second Army and the First Canadian Army.  Established in London during July 1943, under the command of Supreme Headquarters Allied Expeditionary Force (SHAEF), it was assigned to Operation Overlord, the Western Allied invasion of Europe, and was an important Allied force in the European Theatre.  The 21st Army Group operated in Northern France, Luxembourg, Belgium, the Netherlands and Germany from June 1944 until the end of the war in Europe in May 1945, after which it was redesignated the British Army of the Rhine (BAOR).

Supporting paragraphs: Western Allied invasion of Germany Operation Undertone
Answer: World War II