From each number, pich out one word whose underlined part is pronounced differently from the others

I) From each number, pich out one word whose underlined part is pronounced differently from the others.

1) a-perform                            b-colour                       c-boring                                   d-your

3) a-thank                                b-think             c-father                                    d-them

4) a-happen                             b-house                        c-hour                          d-horse

5) a-filled                                b-destroyed                 c-wished                                  d-prepared

6) a-flow                                 b-crowd                       c-cloud                                    d-scout