Biology · PYQ NEET UG 2019(2)

Which of the following conditions will stimulate parathyroid gland to release parathyroid hormone?

1. A
   Rise in blood \( \mathrm{Ca}^{+2} \) levels
2. B
   Fall in active Vitamin D levels
3. C
   Fall in blood \( \mathrm{Ca}^{+2} \) levels
4. D
   Fall in bone \( \mathrm{Ca}^{+2} \) levels