Answer:
c. Mode
Step-by-step explanation:
Mean is the average obtained by adding all values and then dividing by the size of the values. Here, adding A and B etc is not clear.
Median is the middle value of a set of numeric values. To find a median, values should be sort-able from smallest to the largest. If there is no unique middle value, then the average of the middle values has to be taken. Here, average of the two different grades is not clear.
Mode is the value that occurs most often. Clearly C occurs most often.
Mid-range value is the mean of the difference between largest value and the smallest value. Here, difference between A and F is not clear.
Mean,median,Mid-range are applied to numeric values where mode is also suitable for categorical values.
Therefore, the most appropriate measure of central tendency for the data described is mode
