A named narrator has one known pupil but is credibly authenticated. Which statement is correct?

Narrator Anonymity: Wuḥdān, Mubham, Majhūl al-ʿAyn and Mastūr

• A single pupil nullifies every authentication
• He must be classified as mubham
• The one-pupil pattern remains, but does not itself require rejection
• His chain is necessarily mutawātir