The result of attempting to whip cream in a blender is a thick, velvety substance rather than fluffy whipped cream. This is because a blender' s container does not let in enough air to whip cream effectively. Although using a special whipping-cream attachment in a blender can help somewhat, it cannot fully compensate for the container' s poor air intake. If all of the statements above are true, which one of the following must be true? ['The use of a special whipping-cream attachment in a blender does not suffice to whip cream completely effectively.', 'The use of a special whipping-cream attachment in a blender can reduce the total amount of air required to whip cream effectively in that blender.', 'Cream that has been whipped ineffectively generally becomes a thick, velvety substance rather than fluffy whipped cream.', 'When attempting to whip cream in a blender, using a special whipping-cream attachment always produces a fluffier result than could be obtained without using such an attachment.']