Answer:
The correct answer is A. complete protein
Step-by-step explanation:
A complete protein food has all the essential amino acids that are required by the body from outside because the body can not produce these essential amino acids and in most of the cases the animal source of food provides a complete protein source because these contain all the essential amino acids which is hard to find in vegetables.
The animal foods that have complete protein are fishes, eggs, meat products of animals, dairy products like cheese, milk, etc. These amino acids are necessary to build up the body and perform important metabolic functions. Therefore the right answer is A.