Final answer:
The primary conflict in "Where Have You Gone, Charming Billy?" is an internal conflict, as it centers on the protagonist's struggle with fear and anxiety in a war setting.
Step-by-step explanation:
The primary conflict in the story "Where Have You Gone, Charming Billy?" is internal conflict. The story revolves around a young soldier's fear and his struggle to manage and overcome his internal terror in the face of war. The protagonist's challenge is predominantly with his own emotions and thoughts rather than with an external enemy or force. This internal struggle becomes clear as we observe the character's thoughts, feelings, and reactions to the war setting, which is typically loaded with fear and anxiety. Hence, the main conflict is the character's inner battle with his fear.