AT&T Originally Required Special Phone Jacks to Be Installed in Each

Multiple Choice

AT&T originally required special phone jacks to be installed in each customer's house. After the Carterfone Law was passed,all telephone companies had to use standard jacks like AT&T's. This market structure is known as

A) Technical Standard.
B) Dominant Design.
C) Standard Feature.
D) Carterfone Structure.
E) None of the Above.