Vault is configured with the oidc auth method and you need to log in using...

Comprehensive and Detailed In-Depth Explanation:

To authenticate via the OIDC auth method using the CLI, the vault login command with the -method flag is used. The Vault documentation states:

"To authenticate using the CLI, you could use the command vault login and specify the auth methodyou wish to use by using the -method flag. For example, if you wanted to authenticate using OIDC, you could use vault login -method=oidc [options]."

—Vault Commands: login

A: vault login -method=oidc username=bryan is correct, specifying the OIDC method and username:

"The correct command to authenticate using the oidc auth method in Vault is vault login -method=oidc username=bryan."

—Vault Auth: OIDC

B: vault auth oidc is invalid; auth is not a login command.

C: vault login auth/oidc/users/bryan is incorrect syntax; it mimics an API path, not a CLI command.

D: vault login username=bryan lacks the method specification, defaulting to token auth.