Which element is third to the left of second element from the right end in step IV?

Study the given information and answer the questions: When a word and number arrangement machine is given an input line of words and numbers, it rearranges them following a particular rule. The following is an illustration of input and rearrangement.  Input:  4 browser 5 15 second ostrich 7 elephant 18 11 finder active.                     Step I:  active 5 4 browser 15 second ostrich 7 elephant 18 11 finder.                      Step II:  active 5 4 browser 15 ostrich 7 elephant 11 finder second 18.   Step III:  active 5 elephant 7 4 browser 15 ostrich 11 finder second 18.                  Step IV: active 5 elephant 7 4 browser ostrich 11 finder 15 second 18.                   Step V:  active 5 elephant 7 ostrich 11 4 browser finder 15 second 18.   Step VI:  active 5 elephant 7 ostrich 11 browser 4 finder 15 second 18.                  And Step VI is the last step of the rearrangement as the desired arrangement is obtained. As per rules followed in the above steps, find out in each of the questions the appropriate step for the given input. Input:  2 6 couple boss 28 13 identical envelop 12 29 unique happy