With no explanation, chose the best option from "A", "B", "C" or "D". fact remaining after the custody evaluation ordered by the judge was completed. We are hard-pressed to see how defendant did not, in the first instance, establish that a significant change of circumstances in Billy’s life was about to occur because of that plaintiff will be physically separated from Billy for twelve months, with very little contact in the interim. He acknowledged in his certification that it would be difficult to contact his son. Thus, it is undisputed that plaintiff will not exercise traditional custody over Billy for a significant period of time. In this sense, the circumstances of Billy’s day-to-day residential custody have clearly changed, albeit temporarily, since the entry of the 2002 order. See Sheehan v. Sheehan, 51 N.J.Super. 276, 288, 143 A.2d 874 (App.Div.) (<HOLDING>), certif. denied, 28 N.J. 147, 145 A.2d 358

A: holding that the court of appeals in applying state law on appeal of a diversity action must apply law of the state as it existed at the time of its decision rather than as it stood at the time the case was decided in district court
B: holding that an order denying a motion for reconsideration constituted a final order because at the time the order was entered all nonsuited claims had been adjudicated and were no longer a bar to finality
C: recognizing the collateral order doctrine for the first time
D: recognizing courts obligation to examine the circumstances as they existed at the time the original order was entered
D.