Final answer:
Madame Loisel discovers the real cost of the necklace she lost in 'The Necklace' through situational irony.
Step-by-step explanation:
The type of irony that occurs when Madame Loisel discovers the real cost of the necklace she lost in 'The Necklace' is situational irony. Situational irony happens when the outcome of a situation is different from what is expected. In this case, Madame Loisel spends ten years working to pay off what she believes is an expensive replacement necklace, only to find out that the original necklace was a fake and was worth much less than she thought.