An outlier increases the data spread, which is measured by the standard deviation. It can also increase the distance between the mean and median as well as distorting the mean.
So b and d apply.
EXAMPLE
dataset is 1,2,3,6,7,20, where 20 is the outlier. Remove the outlier: 1,2,3,6,7 has a median of 3, a mean of 3.8 and SD of about 2.3; the full dataset has a median of 4.5, a mean of 6.5 and SD of about 6.4.