In a Venn diagram, if the regions representing 'Girls', 'Players', and 'Dancers' intersect, which number would indicate the total number of girls who are both players and dancers?

In a Venn diagram consisting of a rectangle, a circle, and a triangle, if the region enclosed by both the rectangle and the circle but not by the triangle is labeled with a specific number, and that number is 4, which option correctly identifies this value?

In a certain Venn diagram representing professional and demographic categories, if a triangle represents doctors, a rectangle represents women, and a circle represents postgraduates, which region representing the intersection of all three shapes gives the total number of postgraduate female doctors as 15?