A. GSM
B. CDMA
C. LTE
D. All of the above

Solution

D. All of the above

Explanation

Wireless standards used in cellular networks include:

2G (Second Generation):

• GSM (Global System for Mobile Communications)
• CDMA (Code Division Multiple Access)

3G (Third Generation):

• UMTS (Universal Mobile Telecommunications System), which includes WCDMA (Wideband Code Division Multiple Access)
• CDMA2000

4G (Fourth Generation):

• LTE (Long-Term Evolution)
• WiMAX (Worldwide Interoperability for Microwave Access), though it's less commonly used

5G (Fifth Generation):

• NR (New Radio)