Question 21 6 pts Q21. The following table gives the market shares of the companies in the U.S. cell phone industry during January 2023. Company Market share AT &T 25% Verizon Wireless 30% T-mobile 20% Sprint Nextel 15% Google 10% a. Compute the four-firm concentration ratio. Show your work. (1pt) b. Compute HHI before the merger. Show your work. (2pts) c. Use the information in the section "The Department of Justice and FTC Merger Guideline," to predict whether the Department of Justice and the FTC would be likely to approve a merger between AT&T and T-Mobile. Briefly explain your reasoning. (3pts)