In Time Studies, Average Observed Time for an Element Is

In time studies, average observed time for an element is

A) the ratio of normal time to standard time
B) the difference between normal time and the allowance factors
C) for all observations, the sum of all times recorded divided by the number of observations
D) the percent of a worker's time spent performing that element
E) how many observations must be taken in order to achieve a specified level of accuracy