A: San Carlos, California, United States
In April 1956 Ray Dolby, Charles Ginsberg and Charles Anderson of Ampex in San Carlos, California, sold the first practical and commercially successful analog recording video tape, a 2-inch quadruplex video tape (also called 2″ quad, or just quad, for short). They also introduced the first practical and commercial video tape recorder, the VR-1000, at the National Association of Broadcasters convention in November 1956. It cost $50,000.
The machine was first used in a coast-to-coast network TV broadcast in the November 30, 1956 broadcast of "Douglas Edwards and the News" on CBS.
Installation of a VR-1000 at KRLD-TV about 1960 is documented here.