> I was sold on an agreement that by paying a guaranteed monthly fee I could have access to the model at a rate that was lower than the pay-as-you-go rate from the API

Yes, that agreement is there, with the condition that their app is used. That's option B. And I'd think it fairly obvious that if one has to go to extraordinary lengths to gain access, like finding a key under a mat, or needing to login with an official client to gain access to a token for an unofficial client, then - implicitly - it's highly unlikely that that method of access is part of the agreement. And Anthropic has now made it explicitly clear that no, that access method is not part of the agreement.