The correct answer is A) the Civil War.
When Tilden accused Hayes of “waving the bloody shirt,” he meant that Hayes was bringing up the Civil War.
This quote was used during some presidential election campaigns in the 19th century as a sarcastic way to refer to politicians or candidates that used the Civil War reference in an emotional tone. The Northern politicians blamed the Democrats in the south for the blood spilled of the Union Army soldiers that die during the war. But in reality, both Democrats and Republicans used the term and exchanged bitter words.