For the Three Scores 75, 80, 85, Which of the Following

Multiple Choice

For the three scores 75, 80, 85, which of the following is true?

A) $\bar { X } = 81$
B) $\sum ( X - \bar { X } ) = 5.0$
C) $\sum ( X - \bar { X } ) ^ { 2 } = 50.0$
D) All the above