Task: Question Generation
Input (English): Context : Rudolf Trenkel (17 January 1918 -- 26 April 2001) was a German World War II Luftwaffe 138 victories Flying ace and recipient of the coveted Knight's Cross of the Iron Cross (German: Ritterkreuz des Eisernen Kreuzes). 
Answer : Knight's Cross of the Iron Cross
Output (English): What was the award received by Rudolf Trenkel?