The correct option is B 5.27
Here, the number of observations is 11 which is odd.
Arranging the data into ascending order, we get
3, 3, 4, 5, 7, 9, 10, 12, 18, 19, 21
Median =(11+12)th or 6th observation =9
The absolute values of he respective deviations from the median, i.e., |xi−M| are:
6,6,5,4,2,0,1,3,9,10,12
Therefore, ∑11i=1|xi−M|=58andM.D.(M)=111∑11i=1|xi−M|=111×58=5.27