Which is correct: who has or who have?
It depends - if who refers to one person, then use the singular verb.
Will the person who has my book please return it?

If it refers to more than one, then use the plural:

The people who have the tickets with the numbers 23-12-10 will share in the million-dollar jackpot.

It depends on whether the noun that 'who' refers to is singular or plural

eg I have a friend who has red hair.

eg I have friends who have red hair.

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