What method gives each call a special code and spreads it out over available frequencies?

The correct answer is C. CDMA (Code Division Multiple Access).

CDMA is a communication method that allows multiple users to share the same frequency channel by giving each call a unique code. This code spreads the call’s signal across a wider frequency band, allowing different calls to be distinguished from each other even when they are transmitted simultaneously. This increases the capacity of the communication system and provides better quality.

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