Final answer:
DOCSIS is the specification that identifies cable television frequencies dedicated to data transmission, enabling high-speed internet access over cable TV systems.
Step-by-step explanation:
The specification that identifies the cable television frequencies dedicated to data transmission is DOCSIS (Data Over Cable Service Interface Specification). This standard is essential for providing internet services over the same infrastructure that delivers cable television. DOCSIS defines the communication and operation protocols to enable cable modems to provide high-speed internet access. It uses existing cable TV systems to transmit data at high speeds. While other options like MPEG, HDCP, and QAM are related to digital video and protection standards, or modulation techniques, they do not define data transmission standards over cable television networks.