Final answer:
The body loses heat from the groin, feet, and hands in cold water by reducing blood circulation to these extremities to maintain core temperature, which can lead to frostbite in severe cold.
Step-by-step explanation:
When the body is exposed to cold water, it responds by conserving heat for vital organs, often at the expense of the extremities. Specifically, the body loses heat from areas such as the groin, feet, and hands. This occurs because the body reduces blood circulation to these areas to prevent blood from cooling there and to maintain the body's core temperature. In severe cold conditions, this can lead to frostbite due to significantly reduced blood flow to the extremities. Thus, the correct answer to the question 'Where does the body lose heat from in cold water?' is d. The groin, feet, and hands.