Final answer:
AT&T originally stood for a) American Telephone and Telegraph when it was incorporated in 1885.
Step-by-step explanation:
When it was incorporated in 1885, AT&T stood for American Telephone and Telegraph. This company emerged as a result of a series of innovations and business decisions following the patenting of the telephone by Alexander Graham Bell in 1876. The National Bell Telephone Company, backed by Bell, evolved into the American Telephone and Telegraph Company, widely known as AT&T, and held a significant control over the communications industry in the United States, offering a range of services like local and long-distance phone service.
In 1982, due to government litigation, AT&T was split into multiple entities, sparking an era of technological innovation. Services such as call waiting, caller ID, three-way calling, voice mail, mobile phones, and wireless connections to the Internet became widely available. This led to a competitive market with lower prices and a broader range of services, ending the era when you could have any color phone as long as it was black.