Final answer:
The disastrous retreat from Caporetto is best represented by the incident of the British and French soldiers being pinned down on the coast of Dunkirk in late May.
Step-by-step explanation:
The disastrous retreat from Caporetto is best represented by the incident of the British and French soldiers being pinned down on the coast of Dunkirk in late May. Over 300,000 soldiers were trapped, but were successfully evacuated back to England by a flotilla of navy and fishing vessels while the British Royal Air Force held off the German Luftwaffe. Although it was considered a success at the time, it was a clear indicator of the dire situation and retreat the Allies were facing.