Which AAA protocol and feature best support a large ISP that needs to implement detailed accounting for customer invoicing?

Which AAA protocol and feature best support a large ISP that needs to implement detailed accounting for customer invoicing?

• TACACS+ because it combines authentication and authorization, but separates accounting
• RADIUS because it supports detailed accounting that is required for billing users
• TACACS+ because it requires select authorization policies to be applied on a per-user or per-group basis
• RADIUS because it requires select authorization policies to be applied on a per-user or per-group basis

Exam with this question: CCNA Security Chapter 3 Exam (CCNAS v1.2)