Answer
D' = {1,3,5,7,9....19}
Work Step by Step
U = {1,2,3,4...20}
D = {2,4,6,8,....20}
The set D' contains the elements that are not present in the set D.
The elements of set D i.e. 2,4,6,8,....20 must not be present in set D.
The elements of D' are 1,3,5,7,9....19.
Therefore D' = {1,3,5,7,9....19}
