Final answer:
Tom is using AES encryption for WPA2 CCMP.
Step-by-step explanation:
The encryption method Tom is using is AES (Advanced Encryption Standard), which is the correct answer choice A. WPA2 CCMP stands for Wi-Fi Protected Access 2 with Counter Mode Cipher Block Chaining Message Authentication Code Protocol. CCMP is an encryption protocol that uses the AES encryption algorithm to ensure secure communication over a wireless network. AES is a symmetric encryption algorithm that is widely used for its strong security and efficiency.