Question:  David John Shannon was selected to join the newly formed No. 617 Squadron by the most highly decorated serviceman in the country who completed over how many operations at the age of 26?
Sentence (from "Nigger (dog)"): Nigger was a male black labrador retriever belonging to Wing Commander Guy Gibson, V.C., D.S.O., D.F.C. of the Royal Air Force, and the mascot of No. 617 Squadron.
Relevant evidence: No