Which of the following is required under the Biosafety Protocol sponsored by the United Nations in the year 2000?
a. Nations are free to prohibit the import of genetically altered foods without violating free-trade agreements.
b. Genetically altered foods must be shipped in separate containers from foods that are not genetically altered.
c. All genetically altered foods must be clearly labeled as such.
d. Whenever genetically altered foods are offered for sale, comparable food that is not genetically altered must be made available at a comparable price.
