a. n(n + 1)/2 O(n3) b. n(n + 1)/2 0 (na) c. n(n + 1)/2 (n3) d. n(n + 1)/2 12 (n) 3. For each of the following functions, indicate the class (g(n)) the function belongs to. (Use the simplest g(n) possible in your answers.) Prove your assertions. a. (n2 + 1)10 b. V10n2 + 7n +3 c. 2n lg(n + 2)2 + (n + 2)2 lg d. 2n+1 + 3n-1 e. Llogu n]