Which of the following is a characteristic of a nevus?

A nevus, commonly known as a mole, is primarily characterized as a congenital skin mark. This means it is typically present at birth or develops shortly thereafter, distinguishing it from other skin conditions that may appear later in life or result from environmental factors. Nevi can vary in appearance, structure, and color but are fundamentally recognized as benign growths of skin cells resulting from the proliferation of melanocytes, the cells responsible for pigment production.

The other choices you provided describe different skin conditions or features. Eczematic lesions are associated with eczema, which is a chronic inflammatory skin condition characterized by itchy, red, and inflamed skin. Chronic inflammation itself is indicative of ongoing irritation or response to an allergen or irritant and does not solely relate to the benign nature of a nevus. Freckled skin refers to a type of skin pigmentation that typically develops due to sun exposure and is not a congenital feature. Therefore, the defining characteristic of a nevus as a congenital skin mark is what makes it the correct answer in this context.