The Word is:”which”

which

/wɪtʃ/
pronoun & determiner
determiner: which

1. asking for information specifying one or more people or things from a definite set.

“which are the best varieties of grapes for long keeping?”

pronoun & determiner
pronoun: which

1. used referring to something previously mentioned when introducing a clause giving further information.

“a conference in Vienna which ended on Friday”

Source credit: Google

Source credit: Google