A data analyst is working with a data frame named users. It has separate columns for first name $($first$\_$name$)$ and last name $($last$\_$name$).$ The analyst wants to combine the two columns into a single column called full$\_$name, with the first name and last name separated by a space. What code chunk lets the analyst create the full$\_$namecolumn?

$1$ point

merge$($users$,$ "full$\_$name", first$\_$name, last$\_$name, sep $="")$

unite$($users$,$ "full$\_$name", first$\_$name, last$\_$name, sep $=",")$

unite$($users$,$ "full$\_$name", first$\_$name, last$\_$name, sep $="")$

unite$($users$,$ first$\_$name, last$\_$name, "full$\_$name", sep $="")$