A coin sold at auction in 2019 for $6,794,000. The coin had a face value of $1 when it was issued in 1794 and had been previously sold for $215,000 in 1971. a. At what annual rate did the coin appreciate from its first minting to the 1971 sale? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) b. What annual rate did the 1971 buyer earn on his purchase? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) c. At what annual rate did the coin appreciate from its first minting to the 2019 sale? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.)