The following time series shows the number of units of a particular product sold over the past six months. Compute the MAD for the 3-month simple moving average.

Month	Units Sold(Thousands)
1	8
2	3
3	4
4	5
5	12
6	10

a) 28.67

b) 24.33

c) 42.75

d) 3.67

e) 21.50