in the crossover between the baseball section and the soccer section it shows 3 people who play those two sports. those crossovers are with people who play exactly 2 sports, if you add them all 3+5+4 you get 12 people who play only 2 sports.
A cross section is a shape formed by cutting an object using a plane. For this case, a cone is sliced parallel to the slant height so the cross section formed would be a plane with a U-like shape. From the image attached, the correct answer is the second option.
