Which statement about classes provided in the STL is true? Insertion, suppression and lookup in a stat unordered map take a constant time on average, le, the same time no matter the number of elements stored Insertion, suppression and lookup in a std map take a linear time on average, l.e. a time proportional to N where N is the number of elements stored Insertion and suppression in a stad:list take a logarithmic time on overage, le a time proportional to log(N) where N is the number of elements stored