Answer : C
i.e. f(x) =12 when x = 9
Explanation :
Since we have given that

x=9 lies in the interval [9,13]
so f(x) will be 12 for x=9
in another interval i.e (-6,9)
x can't be 9 as it is an open interval which does not include 9 .
so we'll go for f(x)=12 when x=9.