. . . . . . . . is based upon all the observations and it is suitable for further mathematical treatment

Answer: Option B

Arithmetic Mean is based upon all the observations in a given dataset.

It takes into account every value and provides a single representative figure of the data set.

Because it uses all the observations, it is suitable for further mathematical and statistical treatment such as in variance, standard deviation, and correlation calculations.

Other measures like Median or Geometric Mean do not consider all data points in the same way for mathematical manipulation.

Hence, the correct answer is Arithmetic Mean.