Which of the following best explains why protein requirements are increased during pregnancy, serious infection, and recovery from surgery or burns?

• A. These conditions cause shifts in body fluids and increased plasma volume, raising demand for circulating proteins to help maintain oncotic pressure.
• B. Each situation raises need for new tissue or immune proteins, increasing amino acid demand for growth, repair, and host defense. 
• C. They stimulate higher rates of hormone and enzyme production, increasing need for amino acids to support expanded metabolic and regulatory protein synthesis.
• D. They elevate overall energy turnover and tissue remodeling, so dietary protein contributes to both energy provision and substrate for reparative processes.