Explanation:

- Option 1: Raigarh

- Raigarh is a district in Chhattisgarh, India, but it is not known for having a steel plant under SAIL (Steel Authority of India Limited). Raigarh is more popularly associated with Jindal Steel and Power Limited.

- Option 2: Bhilai

- Correct Answer

- Bhilai is home to the Bhilai Steel Plant, which is one of the largest and oldest steel plants in India and operates under SAIL. Located in Chhattisgarh, it is the flagship plant of SAIL and produces a wide range of steel products.

- Option 3: Korba

- Korba is known primarily for its coal mines and power generation industry, with major power plants like the Korba Thermal Power Station. It does not have a steel plant under SAIL.

- Option 4: Bilaspur

- Bilaspur is more recognized for its railway zone headquarters and proximity to coal mines, but it does not have a SAIL steel plant.

Thus, the correct answer is Option 2: Bhilai.