The mean and mean absolute deviation (MAD) of the following data set are given.

1, 2, 3, 5

Mean: 2.75
MAD: 1.25

What effect would adding a 4 to the data set have on the mean and the MAD?
A.
Both the mean and the MAD would decrease.
B.
Both the mean and the MAD would increase.
C.
The mean would decrease; the MAD would increase.
D.
The mean would increase; the MAD would decrease.