I want to know the answer to the following question:
Who was believed to have prevented this from occurring to Mary ?
All the background I'm provided with is that "The proclaimed Roman Catholic dogma states "that the most Blessed Virgin Mary, in the first instance of her conception, by a singular grace and privilege granted by Almighty God, in view of the merits of Jesus Christ, the Saviour of the human race, was preserved free from all stain of original sin."". Is that enough to answer the question?
Answer: yes