Correct option is A
CDMA (Code Division Multiple Access) is a multiple access method where the entire bandwidth is available to all users simultaneously. Each user is assigned a unique code that modulates their signal, allowing multiple users to share the same frequency spectrum without interference. This technology is commonly used in mobile communication systems.
Explanation of Options:
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(b) CSMA (Carrier Sense Multiple Access): A protocol used in local area networks (LANs) where users sense the carrier before transmitting. It does not allow simultaneous access to the entire bandwidth for all users.
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(c) FDMA (Frequency Division Multiple Access): Divides the available bandwidth into separate frequency bands, each allocated to a specific user. Users cannot access the entire bandwidth simultaneously.
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(d) GSM (Global System for Mobile Communications): Uses a combination of FDMA and TDMA (Time Division Multiple Access), which does not allow the entire bandwidth to be used by all users at the same time.
