When Offered as Many Servings of Ice Cream as They

When offered as many servings of ice cream as they would like to eat, people are likely to eat more if they

A) are given small rather than large serving bowls out of which they can eat.
B) are offered servings from a wide variety rather than a small variety of ice cream flavors.
C) are eating the servings of ice cream with smaller rather than larger spoons.
D) are eating the servings of ice cream alone rather than in the presence of others.