Step 1: Understand the question.
We need the constituency where Mamata Banerjee lost to Suvendu Adhikari in a famous contest.
Step 2: Identify it.
The seat was Nandigram in West Bengal.
Step 3: Why it was famous.
Nandigram was central to the anti-land-acquisition movement that earlier boosted the Trinamool Congress. Adhikari won this seat in a close fight, though Banerjee later won from Bhabanipur in a by-election.
Step 4: Rule out others.
Bhabanipur is her home seat; Asansol and Bangaon are other areas. The seat lost to Adhikari was Nandigram.
Step 5: Conclude.
The constituency is Nandigram.
Answer: Nandigram