Which of the following is not a proper way of how spammers get the email Ids?

Which of the following is not a proper way of how spammers get the email Ids? Correct Answer From offline form fill-up documents

Spammers can get email IDs from sources such as data when a user registers to online services, blogs, and sites, databases formed by spiders fetching email Ids from different sources, online ad-tracking tools, email-ID extraction tools, spyware and cookies etc.

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