Concept: If every element of a set D is an element of set E, then D is the subset of E. e.g D={1,2,3}, E={1,2,3,4} As all the elements of D are in E, so D is the subset of E. Now the intersection of two sets D and E is the set of all elements which belong to both D and E. As, in our example the set D={1,2,3} is the intersection of set D and set E.
From the above discussion, it is proved that <span>If set D is not the empty set but is a subset of set E then </span> <span>D ∩ E = D is the true answer.</span>
