Question: According to the doctrine of Immaculate Conception, where was Mary when she first become filled with grace?

Is Orthodox Christians reject the Immaculate Conception dogma principally because their understanding of ancestral sin (the Greek term corresponding to the Latin "original sin") differs from the Augustinian interpretation and that of the Roman Catholic Church. a good answer to this question?

Select from the following. (1). yes; (2). no;
(2).