**Core Concept**
Cushing's syndrome is a disorder caused by excess levels of cortisol in the body, leading to a variety of systemic effects. This excess cortisol can be due to an overproduction of cortisol by the adrenal glands, or due to an overproduction of adrenocorticotropic hormone (ACTH) by the pituitary gland, which stimulates the adrenal glands to produce cortisol.

**Why the Correct Answer is Right**
The correct answer will be one of the options listed below. The features of Cushing's syndrome can include weight gain, particularly in the abdominal area, as well as a redistribution of body fat to the face, neck, and trunk. Other features may include high blood pressure, diabetes mellitus, and osteoporosis. The syndrome can also lead to a range of psychological and behavioral changes, including anxiety, depression, and mood swings.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Cushing's syndrome is not typically associated with weight loss. While some patients may experience a decrease in appetite, the overall effect of excess cortisol is to promote weight gain.
**Option B:** This option is incorrect because Cushing's syndrome can actually lead to an increase in blood sugar levels, rather than a decrease. This is due to the effects of cortisol on glucose metabolism.
**Option C:** This option is incorrect because Cushing's syndrome can actually lead to an increase in blood pressure, rather than a decrease. This is due to the effects of cortisol on vascular smooth muscle and the renin-angiotensin-aldosterone system.

**Clinical Pearl / High-Yield Fact**
One key feature of Cushing's syndrome is the presence of purple striae (stretch marks) on the abdomen, thighs, and arms. These are due to the rapid growth and stretch of skin tissue in response to excess cortisol.

**Correct Answer:** A.