The correct option is B Median will decrease.
Data set in increasing order without including 20 : 12,14,14,14,15,16,18,19
The median of data set = mean of 4th & 5th position
=14+152=14.5
Data set in increasing order including 1 : 1,12,14,14,14,15,16,18,19
The median of data set =14
We can see on including 1, the median of the dataset decreased.
In the data set : 1,16,14,15,19,14,18,12,14
⇒1 is the outlier.