Problem 4: HITTING SET problem is defined as follows: Given a set of elements S, a family of sets C- S1, S2, SnJ, and an integer b, is there a set H with b or fewer elements such that H intersects all sets in the family? For example for the set of elements S {1, 2, 3, 4,5, 6,7} and the family of sets C 11,2, 3), [2,4,63, [3,5), {1, 5, 6,7), 3,7)), there is a hitting set of size b= 3. (e.g. H= {3.4.7). Show that HITTING SET problems NP-Complete. (Hint: Use Vertex Cover problem)