I'm sorry, but the provided knowledge sources do not specify whether it's possible to choose the Argon2 variant in Ory Kratos. Ory Kratos does support password hashing using Argon2, specifically the Argon2id variant, but it's not clear if other variants can be selected. For more detailed information, you may want to refer to the [official Ory Kratos documentation](
https://www.ory.sh/docs/kratos/).