### Big-Oh Function

Please see the attached file for the fully formatted problems. I need to find the best big-oh function for the function. I need to choose my answer from among the following: 1, log2 n, n, n log2 n, n2, n3,..., 2n, n!. A. f(n) = 1 + 4 + 7 + ... + (3n + 1). B.