A
4 1 2 3
B
3 2 1 3
C
2 4 3 1
D
1 3 2 1
Correct answer: (a) 4 1 2 3
Explanation
- A
4 1 2 3
Talcher (Takhir) coal is in the Mahanadi valley (Odisha) — 4; Karanpura (Karnapura) in the Damodar valley — 1; Singrauli in the Son valley — 2; Singareni (Singreni) in the Godavari valley — 3. Code 4 1 2 3 is the official key.
- B
3 2 1 3
3 2 1 3 repeats 3 and misplaces Talcher on the Godavari. Incorrect.
- C
2 4 3 1
2 4 3 1 puts Talcher on the Son and Karanpura on the Mahanadi. Swapped.
- D
1 3 2 1
1 3 2 1 repeats 1 and puts Talcher on the Damodar. Wrong.
Summary. Official key is (a) 4 1 2 3. Talcher–Mahanadi, Karanpura–Damodar, Singrauli–Son, Singareni–Godavari.