"At times he regarded the wounded soldiers in an envious way. He conceived persons with torn bodies to be peculiarly happy. He wished that he, too, had a wound, a ________ of courage."

The answer is, predictably, 'red'.

"At times he regarded the wounded soldiers in an envious way. He conceived persons with torn bodies to be peculiarly happy. He wished that he, too, had a wound, a red badge of courage."