Step 1: Understanding the Concept:
Every enzyme is a protein folded into one exact three-dimensional shape, and that shape is what lets it grip its substrate and speed up a reaction. Temperature changes the amount of motion inside the protein, so enzyme activity rises and falls with temperature in a fairly narrow band.
Step 2: Key Approach:
Plot enzyme activity against temperature and you get a curve that rises, peaks at one optimum value, then drops sharply once the protein starts to unfold (denature). For any enzyme working inside the human body, that optimum lines up with the temperature the body normally keeps itself at.
Step 3: Detailed Explanation:
The human body holds its core temperature at about $37^{\circ}\text{C}$ through homeostatic control, and this is exactly the value evolution has tuned our enzymes to work best at. At $17^{\circ}\text{C}$ or $27^{\circ}\text{C}$, molecules move too slowly and collide too rarely, so reactions crawl. At $47^{\circ}\text{C}$, the extra heat energy is enough to break the weak bonds holding the enzyme's shape together, and the protein denatures, losing its activity for good, not just slowing down. So $37^{\circ}\text{C}$ is the single value on the curve where activity peaks without any risk of unfolding.
Step 4: Final Answer:
Human enzymes work best at the body's own core temperature, $37^{\circ}\text{C}$, so option 3 is correct.