Arrange the following in sequence to find variance of individual observation. 

(A) compute $ \bar{X} $ of observation $x_1, x_2 \dots x_n$ 

(B) square the deviation obtain sum $ \sum_{i=1}^{n} (x_i-\bar{X})^2 $ 

(C) divide the sum $ \sum_{i=1}^{n} (x_i-\bar{X})^2 $ by $n$ 

(D) take deviation of observation from mean that is $(x_i-\bar{X})$ 

(a) A, B, C, D 

(b) A, D, B, C 

(c) A, C, B, D 

(d) B, C, D, A