An organization tasks a network consultant with comparing the costs and requirements for the various types of Carrier Ethernet. The consultant selects a carrier ethernet that uses digital subscriber line $($DSL$)$ variants such as single$-$pair high$-$speed DSL $($SHDSL$)$ and very high$-$speed DSL $($VDSL$)$ to overcome the usual distance limitations of copper Ethernet. What type of carrier ethernet was selected by the consultant?

A$.$Ethernet over Copper

B$.$Ethernet over Fiber

C$.$E$-$line

D$.$E$-$LAN