Please decide how far you trust this user to correctly verify other users' keys (by looking at passports, checking fingerprints from different sources, etc.)
1 = I don't know or won't say
2 = I do NOT trust
3 = I trust marginally
4 = I trust fully
5 = I trust ultimately
This reveals a lot about the assumptions of PGP and the problem it was trying to solve...
The menu clearly focuses on real-world identities, trying to get users to establish ‘trust’ that people correspond to the cyber-space identities. (Those digital identities are the keys: anyone with the key is indistinguishable from anyone else who has it.) Why else is the focus on “verifying” by looking at passports and fingerprints?
In short, PGP was the first Google+: built by nerds as an identity service for the masses… that failed to become mainstream.