Final answer:
The merger between AT&T and T-Mobile would tend to reduce competition in the United States cellular phone market.
Step-by-step explanation:
The statement that a merger between AT&T and T-Mobile were tend to reduce competition in the United States cellular phone market is true.
When companies merge, it often leads to a reduction in competition because there are fewer players in the market. In the case of AT&T and T-Mobile, their merger would have resulted in a decrease in the number of major cellular phone service providers in the United States. This could potentially lead to higher prices for consumers and less incentive for innovation and improvement in service quality.
Historically, when AT&T merged with BellSouth in 2006, there were concerns about reduced competition and higher prices. Economists are still studying whether these mergers have benefited or harmed consumers in the long run.