Answer:
The answer is A. Quadrature amplitude modulation
Step-by-step explanation:
Quadrature amplitude modulation or QAM is a type of digital modulation used in telecommunications.
QAM is a technique that involves the combination of two amplitude-modulated (AM) signals within a single communication channel through the use of analog modulation or amplitude modulation techniques to optimize communication.
QAM results in more efficient bandwidth for better communication.