Nutritionist: Vitamins synthesized by chemists are exactly the same as vitamins that occur naturally in foods. Ttherefore, it is a waste of money to pay extra for brands of vitamin pills that are advertised as made of higher-quality ingredients or more natural ingredients than other brands are. The nutritionist's advice is based on which one of the following assumptions? ['All brands of vitamin pills contain some synthesized vitamins.', 'Some producers of vitamin pills are guilty of false advertising.', 'It is a waste of money for people to supplement their diets with vitamin pills.', 'There is no nonvitamin ingredient in vitamin pills whose quality makes one brand worth more money than another brand.']