In this problem it will be useful to recall the following properties of logarithms: log(xy) = log(x) + log(y) and log(x) = a log(x). Find the least integer k such that f(n) is O(n) for each of the following functions: a) f(n) = n log(4") (b) f(n) 18+28+. = (c) f(n) = log(n!)| + n d) f(n) log(n") = n+1