Correct option is B
When we arrange the data in a manner = 11, 11, 12, 12, 13, 13, 13, 15, 18
The total number is 9 then median of the data nth number = (n + 1)/2 = (9 + 1)/2 = 10/2 = 5th
The 5th number would be the median of the data = 13
The mode of the data = 13
(Because 13 repeated largest time in given data)
Sum of the mode and median of the data = 13 + 13 = 26

