Construct a quiz question about the country of France.
Which river, the longest in France, flows through the cities of Orleans, Tours, and Nantes before emptying into the Atlantic Ocean?
Complete the following task based on the instruction and optional input provided.### Instruction:
Construct a quiz question about the country of France.

### Output:
Which river, the longest in France, flows through the cities of Orleans, Tours, and Nantes before emptying into the Atlantic Ocean?