Question: Which group do marsupials and placentals belong to?

Is "Since this ancestor lived in the Jurassic period, Rowe's definition excludes all animals from the earlier Triassic, despite the fact that Triassic fossils in the Haramiyida have been referred to the Mammalia since the mid-19th century." the correct answer?
Choose from: (a). yes; (b). no;
(b).