b. John trusts me—John the agent.
As the relative is only the antecedent in another form, it may change its case according to the construction.
1. I trust John—(2) John trusts me.
2. I trust John—(2) He trusts me.
3. I trust John—(2) Who trusts me.
4. John trusts me—(2) I trust John.
5. John trusts me—(2) I trust him.
6. John trusts me—(2) I trust whom.
7. John trusts me—(2) Whom I trust.
8. John—(2) Whom I trust trusts me.