Sentence:  “I cannot do it, Sir !” was his reply. “I fire into their ranks, and that does as well ; but to single out one among them, and mark him for death, would lie upon my mind afterwards.” The man who could feel thus was worthy of a better station than that in which his lot had been <WSD>assigned.</WSD> 
Meaning of the word marked with <WSD> tags:  To allot or give something as a task.