Answer:
Option a. Production of white blood cells
Explanation:
The endocrine system is the system that involves the organs and glands that produce and secretes the hormones that acts on various other activity to regulate responses or activity.
Major function and examples of endocrine system are :
Aldosterone helps in fluid absorption in kidney
Thyroxine helps in regulating body metabolism and energy
Testosterone is responsible for sperm production is regulated
But, WBC formation is not regulated by hormones.
Thus, the correct answer is: option a. Production of white blood cells
