Final answer:
Moon face' is an easily observable symptom of Cushing's syndrome, which is caused by the overproduction of cortisol. This condition also presents various other symptoms and requires treatment tailored to its underlying cause. Option C is correct.
Step-by-step explanation:
The condition that is described as having the 'easily observable symptom of hypercortisolism' is known as Cushing's syndrome. This syndrome is characterized by the overproduction of cortisol due to various causes, including a pituitary tumor. Moon face is a distinctive sign where fat deposits give the face a rounded appearance. Other signs and symptoms of Cushing's syndrome can include obesity, diabetes, high blood pressure, osteoporosis, depression, and stretch marks due to thinning skin.
Treatment for Cushing's syndrome varies depending on the cause but may involve surgery, radiation therapy, medications, or discontinuing the use of cortisol ointments.