Final answer:
Vitamin D is the fat-soluble nutrient that regulates calcium and bone metabolism, critical for calcium absorption and bone health.
Step-by-step explanation:
The fat-soluble nutrient that regulates calcium and bone metabolism is Vitamin D. Vitamin D plays a vital role in enabling calcium absorption from the small intestine, which is essential for strong bone formation and maintenance. Without sufficient Vitamin D, calcium cannot be properly absorbed, leading to potential bone health issues such as rickets in children. Moreover, Vitamin D is involved in bone remodeling, though its role in this process is less understood than its role in calcium absorption.
Concerning other options provided in your question, Vitamin A is key for maintaining connective tissues, Vitamin K is essential for blood clotting and also supports bone mineralization, whereas Vitamin E acts as an antioxidant.