The correct answer is D. Meat, Milk, Egg.
Biological complete proteins are proteins that contain all nine essential amino acids that the human body cannot produce on its own. These amino acids are essential for growth, development, and repair of tissues.
Meat, milk, and eggs are all good sources of biological complete proteins. Other good sources of biological complete proteins include fish, poultry, tofu, and quinoa.
Potatoes, onions, and carrots are all good sources of carbohydrates, but they do not contain all nine essential amino acids. Apples are a good source of vitamins and minerals, but they also do not contain all nine essential amino acids. Wheat is a good source of carbohydrates and protein, but it does not contain all nine essential amino acids. Rice is a good source of carbohydrates, but it does not contain all nine essential amino acids. Butter is a good source of fat, but it does not contain any protein.
Therefore, the correct answer is D. Meat, Milk, Egg.