We have been given a universal set U and a set A defined as follows.
&U={1,2,3,4,5,6,7,8 }
&A={ 1, 2, 3, 4 }
We are asked to find A'. In order to do this, let's identify the elements of the universal set.
&U={ 1, 2, 3, 4,5,6,7,8 }
Since the complement of a set is the set of all elements in the universal set that are not in the set, we can construct A' as shown below.
&A'={5,6,7,8 }
Therefore, the answer is B.
