Which of the following is an example of a complete protein source?

A complete protein source contains all nine essential amino acids that the human body cannot synthesize on its own. Eggs are considered one of the best sources of complete protein because they have a balanced amino acid profile that includes all essential amino acids in adequate amounts. This makes them particularly valuable for individuals who are trying to meet their protein needs for muscle maintenance and overall health.

In contrast, rice, beans, and peanuts are sources of protein but do not provide all essential amino acids in sufficient quantities. For instance, rice is low in lysine, beans are low in methionine, and while peanuts do have some essential amino acids, they do not have a complete profile either. Therefore, eggs stand out as the optimal choice for a complete protein source among the options provided.