A 58-year-old man presents with a 3-week history of bright-red bleeding per rectum and a palpable mass at the anal verge that he can push back inside. Anoscopy reveals internal hemorrhoids at the 3, 7, and 11 o'clock positions. The structure marked **D** in the diagram indicates that manual reduction is required. What is the grade of internal hemorrhoids in this patient, and what is the most appropriate first-line management?