There is a set of ground elements E = {e1, e2, . . . , en} and a collection of m subsets S1, S2, . . . , Sm of the ground elements (that is, Si ⊆ E for 1 ≤ i ≤ m).The goal is to select a minimum cardinality set A of ground elements such that A contains at least one element from each subset Si.Give a polynomial time algorithm for this problem or state the decision version of this problem and prove that it is NP-complete.