The correct answer is (b) Dalli-Rajhara.
Rourkela Steel Plant is a steel plant located in Rourkela, Odisha, India. It is one of the largest steel plants in India. The plant was established in 1954 with the help of the Soviet Union.
The plant gets its supplies of iron ore from Dalli-Rajhara, which is a town in the Jharsuguda district of Odisha. Dalli-Rajhara is one of the largest iron ore mines in India.
The other options are incorrect. Keonjhar is a district in Odisha, but it is not a major source of iron ore. Kamangundi is a village in the Mayurbhanj district of Odisha, and it is not a major source of iron ore either. Mayurbhanj is a district in Odisha, but it is not a major source of iron ore.