Seraphina is driving two hours to visit her family. For the first hour, she traveled at a speed of 62 miles per hour. Then, in the second hour, she traveled at a speed of 74 miles per hour. What is the percentage increase of Seraphina's speed? If necessary, round to the nearest tenth of a percent.
A. 19.4%
B. 80.6%
C. 83.8%
D. 16.2%
