Deion is hoping to fill his diet with more complete proteins. Which would be a good food for him to add to his diet to accomplish this?

To increase the intake of complete proteins, Deion should add foods that contain all nine essential amino acids. Out of the given options, poultry is the best choice as it is a rich source of complete proteins. Nuts and grains are incomplete proteins, meaning they lack one or more essential amino acids. While vegetables can be a good source of protein, they are usually incomplete proteins and may not provide all the essential amino acids that Deion needs. Therefore, the correct answer is C.