When Hakeem runs the 400-meter dash, his finishing times are normally distributed with a mean of 70 seconds and a standard deviation of 2 seconds. Using the empirical rule, determine the interval of times that represents the middle 68% of his finishing times in the 400-meter race. a) Between 66 and 74 seconds b) Between 68 and 72 seconds c) Between 70 and 74 seconds d) Between 66 and 72 seconds