Correct Answer: SNRUEMB
Explanation:
1 2 3 4 5 6 P R O B L E 7 M ⇒ 7 1 6 2 5 3 M P E R L O 4 B
Similarly, 1 2 3 4 5 6 N U M B E R 7 S ⇒ 7 1 6 2 5 3 S N R U E M 4 B