How can one know if their religion is the true one since there are over 4000 ?

Every person claims their religion to be true, how they know if theirs is the right one between over 4000+ religions? + how come they know if their religion is just "something" because of where they were born or what influenced (a. k. a brainwashed) them during childhood. would muslims really be muslims if they were raised in a committed christian family, vice versa for all other religions.

How can one know if their religion is the true one since there are over 4000 ?
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