The STeiNeR TrEE problem is as follows. Given an undirected graph G-(V, E) with nonnegative edge costs and whose vertices are partitioned into two sets, R and S, find a tree T CS G such that for every v E R. v E T with total cost at most C. That is, the tree that contains every vertex in R (and possibly some in S) with a total edge cost of at most C. Prove that this problem is NP-complete. The STeiNeR TrEE problem is as follows. Given an undirected graph G-(V, E) with nonnegative edge costs and whose vertices are partitioned into two sets, R and S, find a tree T CS G such that for every v E R. v E T with total cost at most C. That is, the tree that contains every vertex in R (and possibly some in S) with a total edge cost of at most C. Prove that this problem is NP-complete