You are designing a solution that needs to support 30 IP phone users. Which switch model and how many switches does the Cisco Single-Site Secure Network Foundation1.1 Desing and Implementation Guide suggest for the solution？（）

• A、1 Catalyst Express 500G-12TC,1 Catalyst 3750G-12S-S
• B、1 Catalyst 3750G-12S-S,1 Catalyst Express 500-24PC
• C、2 Catalyst Express 500G-12TC
• D、2 Catalyst 3750G-12S-S,1 Catalyst Express 500-24PC
• E、2 Catalyst Express 500-24PC
• F、2 Catalyst 3750G-12S-S