A humanities professor assigns letter grades on a test according to the following scheme. A: Top 12% of scores B: Scores below the top 12% and above the bottom 58% C: Scores below the top 42% and above the bottom 19% D: Scores below the top 81% and above the bottom 10% F: Bottom 10% of scores Scores on the test are normally distributed with a mean of 74.6 and a standard deviation of 9.1. Find the numerical limits for a C grade. Round your answers to the nearest whole number, if necessary.