Final answer:
The z-score cannot be calculated without the mean and standard deviation, but based on the available options, the most likely z-score for Daniel's exam grade of 64 would be -0.67.
Step-by-step explanation:
The z-score is a measure of how many standard deviations a particular value is from the mean. To calculate the z-score, we need to know the mean and the standard deviation of the data set. Since the question does not provide this information, we cannot calculate the exact z-score for Daniel's exam grade of 64.
However, we can make an estimate based on the given options. The z-score ranges from -3 to +3, according to the empirical rule. A z-score of -2.67 would be significantly below the mean and unlikely for a exam grade of 64. Similarly, a z-score of -1.67 and -0.67 would indicate below average performance, but not as extreme as the first option. Therefore, based on an estimate, the most likely z-score for Daniel's exam grade of 64 would be (c) -0.67.