Final answer:
During pregnancy, the placenta produces a hormone called hPL, which decreases the effectiveness of insulin.
Step-by-step explanation:
The correct answer is B) hPL, which decreases the effectiveness of insulin. During pregnancy, the placenta produces a hormone called Human Placental Lactogen (hPL), also known as Human Chorionic Somatomammotropin (hCS).
This hormone decreases the effectiveness of insulin, making it harder for insulin to regulate blood glucose levels. As a result, pregnant individuals with diabetes may require higher doses of insulin to maintain proper blood sugar levels.