C. 88
Feedback Mean score of 9 innings = 58 runs.
Total score of 9 innings = (58 x 9) runs = 522 runs
A required mean score of 10 innings = 61 runs.
Required total score of 10 innings = (61 x 10) runs = 610 runs.
Number of runs to be scored in the 10th innings
= (total score of 10 innings) - (total score of 9 innings)= (610 -522) = 88.
Hence, the number of runs to be scored in the 10th innings = 88.