Explanation
The correct answer is C. DSL.
DSL stands for Digital Subscriber Line, which is a technology that delivers internet over a copper medium, such as a telephone line. DSL uses different frequencies than voice calls, so it can provide both internet and phone service simultaneously. DSL can offer faster speeds than dial-up, but it depends on the distance from the service provider and the quality of the copper line .
The other options are not technologies that deliver internet over a copper medium. ONT stands for Optical Network Terminal, which is a device that converts optical signals from a fiber optic cable to electrical signals for a copper cable or a wireless router. ONT is used for fiber-to-the-home (FTTH) internet service, which delivers internet over a fiber optic medium. SDN stands for Software Defined Networking, which is a technology that allows network administrators to manage and control network resources and traffic using software applications. SDN is not related to the physical medium of internet delivery, but rather to the logical layer of network configuration and optimization. WISP stands for Wireless Internet Service Provider, which is a company that delivers internet over a wireless medium, such as radio waves or microwaves. WISP can provide internet access to rural or remote areas where wired connections are not available or feasible.