Let f(n) = n (n + 1) / 2. Of the following possibilities, state which are true about f and of those, which one best describes the asymptotic class of f?
(Be sure to argue your answers.) a. T(n2) b. O(n2) c. O(n2) d. T(n (n + 1) / 2) e. O(n (n + 1) / 2) f. O(n (n + 1) / 2) g. T(n3) h. O(n3) i. O(n3) j. T(n log n) k. O(n log n) l. O(n log n) m. T(n) n. O(n) o. O(n)