Answer: 20 milligram per kilo gram of food.
Step-by-step explanation:
FDA: Food and drug Administration
According to FDA, product labelled as gluten free must contain 20 parts per million gluten. This also means that 20 milligram of gluten per kilo gram of food. or we can also say that 20 milligrams of gluten per 35.27 ounce of food.
Hence,the correct answer is option (c).