**Core Concept**
Glucocorticoids and catecholamines are released in response to stress, activating the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system, respectively. This stress response is crucial for maintaining homeostasis during surgery, particularly in diabetic patients (DM) who require precise glucose control.

**Why the Correct Answer is Right**
During stress, the hypothalamus releases corticotropin-releasing hormone (CRH), which stimulates the pituitary gland to release adrenocorticotropic hormone (ACTH). ACTH then stimulates the adrenal glands to release cortisol, a glucocorticoid hormone that increases gluconeogenesis, glycogenolysis, and lipolysis, ultimately raising blood glucose levels. Additionally, the sympathetic nervous system is activated, releasing catecholamines (e.g., epinephrine and norepinephrine) that also contribute to increased blood glucose levels by stimulating glycogenolysis and gluconeogenesis. This hormonal response is particularly relevant in diabetic patients, as it can lead to hyperglycemia and worsen metabolic control.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the hormonal response during stress in surgery, especially in diabetic patients.
* **Option B:** This option is incorrect because insulin is actually decreased during stress, as the body prioritizes glucose release for energy production.
* **Option D:** This option is incorrect because parasympathetic activity is decreased during stress, as the sympathetic nervous system takes over to prioritize energy production.

**Clinical Pearl / High-Yield Fact**
During stress, the body prioritizes glucose release for energy production, which can lead to hyperglycemia in diabetic patients. This emphasizes the importance of close glucose monitoring and insulin management during surgery in diabetic patients.

**Correct Answer: C. Cortisol**