GRAMMAR – WHOSE vs WHO IS
WHOSE is a possessive pronoun that asks to whom something belongs.
WHO’S is a contraction of who+is or who+has.
BE CAREFUL because they sound exactly the same. [hooz]
The easiest way to tell them apart is to look for the verb. If you cannot find a verb then it must be part of who+is or who+has. Otherwise, it must be whose.