3. [42 pts]Prove the following using the method that relies on "Universal Generalization". (Typically, these proofs start with something like: Let a N, selected arbitrarily ) a. (Vn N+)[n2 + 4n + 3 is composite]. b. (Vn E N)In2 +n is evenj. Hint: Consider two cases: n is even or n is odd. c. For all n E N, if n is the product of four consecutive integers, then n +1 is a perfect square