Whose sneakers are/is those?
They're her sneakers.
Whose shirt are/is that?
It's his shirt.
Whose skirt are/is that?
It's her skirt.
Whose hat are/is that?
It's his hat.
Whose boots are/is those?
They're her boots.
Whose sweater are/is that?
It's his sweater.
Whose shorts are/is those?
They're their shorts.
Whose pants are/is those?
They're his pants.
Whose pants are/is those?
They're his pants.
Whose jacket are/is that?
It's his jacket.
Whose skirt are/is that?
It's her skirt.