Given:

To find:
The missing value.
Solution:
Let x be the missing value.
We have,


Subtract
from both sides.




Multiplying both sides by 5, we get

So, the missing value is 3.
Therefore, the correct option is C.
The IQR or interquartile range is the difference between Q1 and Q3, also know as the upper and lower quartiles.
I think that the answer is A.