If x$=$c$("$CE$","$IE$","$EE$","$DS$","$DS$","$EE$","$IE$"),$ then which of the following commands will display the following output?

Output:

$[1]$ CE IE EE DS DS EE IE

Levels: CE DS EE IE

a$.$ table$($x$)$

b$.$ x$=$c$("$CE$","$IE$","$EE$","$DS$","$DS$","$EE$","$IE$")$ data.frame$($x$)$

c$.>$x$=$c$("$CE$","$IE$","$EE$","$DS$","$DS$","$EE$","$IE$")$

d$.>$x$=$c$("$CE$","$IE$","$EE$","$DS$","$DS$","$EE$","$IE$")>$factor$($x$)$