When is it reasonable for someone to consider they've been ghosted?

If someone hasn't heard from their girlfriend/boyfriend despite attempts of reaching out, when should ghosting be remotely considered a possibility?

Within 24 hours
Within 48 hours
Around 72 hours
3-5 days
Longer than 5 days
Select gender and age to cast your vote:
When is it reasonable for someone to consider they've been ghosted?
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