By definition the interquartile range or IQR is obtained when the 25th percentile or [tex] Q_{1} [/tex] is subtracted from the 75th percentile or [tex] Q_{3} [/tex].
Thus, from the above definition, the formula for IQR is:
[tex] IQR=Q_{3}-Q_{1} [/tex]
As we can see from the provided options that the definition of IQR matches the expression provided in Option A and thus, Option A is the correct answer.
