Which statement best distinguishes a non-canonical reading from canonically transmitted Qurʾān?

The Four Proofs: Fiqh, Uṣūl al-Fiqh and Kalām

• Every reliably reported non-canonical reading becomes mutawātir Qurʾān
• They differ; a reliable transmission may still enter some legal argumentation
• A non-canonical reading can be considered only if it becomes canonical
• The legal authority of non-mutawātir readings is identical across schools