Final answer:
Claude Monet focused on the door of the central portal and the spires at the top of the facade while painting Rouen Cathedral: The Portal (Sunlight). He captured the changing light on the surface of the cathedral and used short brushstrokes to define the sculpted stone.
Step-by-step explanation:
Claude Monet focused on the door of the central portal and the spires at the top of the facade while painting Rouen Cathedral: The Portal (Sunlight). He captured the changing light on the surface of the cathedral and used short brushstrokes to define the sculpted stone. The facade was painted at an angle to create a sense of depth and perspective in the artwork.