X $=\{$a$,$ b$,$ c$,$ d$\}$

Y $=\{5,6,7,8,9\}$The function f: X $->$ Y is defined as: f $=\{($d$,9),($b$,9),($c$,8),($a$,6)\}.$What is f$($d$)?$ f$($d$)=$

Ex: $7$

Select the elements that are in the range of f: