Final answer:
The poem "Lather and Nothing Else" is principally about the moral dilemmas faced in war, using shaving as a metaphor for personal ethical decisions in times of conflict. The correct answer is option C.
Step-by-step explanation:
The poem "Lather and Nothing Else" primarily focuses on C. Moral dilemmas in war. It explores the internal conflict of a barber who is given the opportunity to kill a military figure during a war, using the act of shaving as a backdrop for a much deeper moral and ethical debate. The poem grapples with the concepts of duty, personal ethics, and the value of human life amidst the pressures and realities of a wartime society.