**Core Concept**
Adrenal incidentalomas are benign adrenal tumors discovered incidentally on imaging studies performed for unrelated reasons. The management of these tumors involves a multidisciplinary approach, considering both the benign and malignant potential of the tumor, as well as the risk of hormonal overproduction.

**Why the Correct Answer is Right**
Surgery is indicated in cases of adrenal incidentaloma when there is evidence of malignancy, such as invasion of adjacent structures, metastatic disease, or a high risk of malignancy on histopathological examination (e.g., large size, irregular shape, or positive fine-needle aspiration cytology). Additionally, surgery may be considered in cases of functional tumors (e.g., pheochromocytoma, aldosteronoma) to prevent potential complications or in symptomatic patients.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a small size (<4 cm) or non-functional nature of the tumor does not preclude the need for surgical evaluation, especially if there are concerns about malignancy or hormonal overproduction. **Option B:** This option is incorrect because a low cortisol production is not a contraindication to surgery, and in fact, surgery may be indicated in cases of adrenal insufficiency due to tumor destruction of the adrenal gland. **Option C:** This option is incorrect because a high cortisol production (Cushing's syndrome) is a contraindication to surgery, as it may be a functional tumor requiring medical management rather than surgical intervention. **Clinical Pearl / High-Yield Fact** The presence of a high risk of malignancy or functional characteristics (e.g., pheochromocytoma, aldosteronoma) on imaging or biochemical evaluation should prompt surgical evaluation in cases of adrenal incidentaloma. **Correct Answer:** C.