Consider the following: 1. Bluetooth device 2. Cordless phone 3. Microwave oven 4. Wi-Fi device Which of the above can operate between 2-4 and 2.5 GHz range of radio frequency band?

1. The question asks which of the listed devices operate in the 2.4 to 2.5 GHz radio frequency band, which is part of the ISM (Industrial, Scientific, and Medical) bands. 2. Bluetooth devices operate in the 2.400 to 2.4835 GHz band (Statement 1 is correct). 3. Many modern cordless phones operate in designated bands like DECT (1.9 GHz) or older ones (like 900 MHz), but some models, especially older or simpler ones, also utilize the 2.4 GHz band (Statement 2 is correct). 4. Microwave ovens operate by generating radio waves typically centered around 2.45 GHz to heat food (Statement 3 is correct). 5. Wi-Fi devices (following IEEE 802.11 standards like 802.11b, 802.11g, 802.11n, and newer ones) commonly operate in the 2.4 GHz band (2.400 to 2.4835 GHz), although many also use the 5 GHz band (Statement 4 is correct). 6. Since all four devices can operate within this frequency range, option (D) is correct.