In a CDO structure, when economic condition turns out to be better than previously expected, the cash flow from the pool of underlying assets (such as mortgage loans or consumer loans) is more than the level reflected in the original(previous) pricing of the tranches. In this scenario, which trancherate of return will turn out to be higher than others? (1) Senior tranche; (2) 2 Mezzanine tranche; (3) Junior tranche