How Does the Reproductive System Contribute to Osteoporosis

How does the reproductive system contribute to osteoporosis?

A) Calcium ions released from the bones are excreted.
B) Immune cells resist infections and release chemicals that promote tissue repair.
C) Decreased estrogen levels following menopause contribute to the disease.
D) Lack of exposure to sunlight reduces vitamin D production and decreases calcium absorption.
E) Excessive smoking lowers estrogen levels, which increases bone loss.