Which of these is not a cousin?

Cousins Chris and Mary and their rambunctious offspring have returned from their Caribbean cruise sun-kissed and happy. They submitted this stellar photo of Chris, Mary and Mo with major famous celebrity Merrill Osmond of the Osmond Brothers!! We were very impressed, especially when Chris reminded us of their immortal hit, "One Bad Apple Doesn't Spoil the Whole Bunch Girl." Mary allowed as to how Donny is her favorite Osmond, but we won't tell Merrill that.