Read the passage from "Children of the Wartime Evacuation.” It was codenamed Operation Pied Piper. Who on earth came up with that name? Not a mother, that is certain. After all, the piper leads the children of Hamelin away from the town, never to return. Over the six years of the war, more than two million children were sent away from their family homes. Most returned, but how they had changed and how the separation affected their relationships with their families is seldom considered.

–"Children of the Wartime Evacuation,”
Julie Summers

Which detail best supports the central idea that Operation Pied Piper affected many children?

The war lasted a total of six years.
A mother likely did not come up with the name for the operation.
Over two million children had to leave their families during the war.
The original Pied Piper of Hamelin took children and never returned them.