Which of the Following Could Be Used as a Measure $\sum \left( X _ { 1 } - \mu \right) ^ { 2 } \cdot P \left( X _ { 1 } \right)$

Multiple Choice

Which of the following could be used as a measure of spread of a probability distribution.

A) $\sum \left( X _ { 1 } - \mu \right) ^ { 2 } \cdot P \left( X _ { 1 } \right)$
B) $\sum \left( X _ { 1 } - \operatorname { median } ( X ) \right) ^ { 2 } \cdot P \left( K _ { l } \right)$
C) $\sum \left| X _ { i } - \mu \right| \cdot P \left( X _ { i } \right)$
D) All of these formula measure spread