In this study for the painting Christmas Day 1900, Michael Ancher focuses on how the figure to the far right should hold the Bible. Hence, he included none of the other figures.
He presumably got his sister-in-law Marie Brøndum to sit for him, for Ancher relied on models when working. He would have seen no reason to inconvenience the other women by having them sit in for this particular sketch, so Marie is all alone. Her pose and the placing of the Bible in front of her exactly match those of the final painting, demonstrating that by this point Ancher was sure of what he wanted.