**Core Concept**
Albumin is a major protein in the blood, synthesized in the liver, and plays a crucial role in maintaining blood volume, transporting hormones, vitamins, and drugs, and regulating the osmotic pressure of blood. Serum albumin levels are often used as a marker of nutritional status, with low levels indicating malnutrition.

**Why the Correct Answer is Right**
A serum albumin level between 2.8 and 3.5 g/dL is generally considered within the normal range. However, mild malnutrition is often defined as a serum albumin level between 2.5 and 2.8 g/dL. This range indicates a slight decrease in serum albumin, which can be due to inadequate protein intake, chronic disease, or inflammation. The liver's ability to synthesize albumin is also affected by factors such as liver disease, nephrotic syndrome, and chronic kidney disease.

**Why Each Wrong Option is Incorrect**
**Option A:** A serum albumin level below 2.5 g/dL is generally considered moderate to severe malnutrition, making this option incorrect for mild malnutrition.
**Option B:** There is no universally accepted definition of mild malnutrition based on serum albumin levels, but a level below 2.5 g/dL is often used to indicate moderate malnutrition.
**Option C:** A serum albumin level above 3.5 g/dL is generally considered normal, and this option does not accurately represent mild malnutrition.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
When evaluating a patient's nutritional status, it's essential to consider serum albumin levels in conjunction with other markers, such as prealbumin and transferrin, as well as clinical indicators of malnutrition, such as weight loss, muscle wasting, and poor wound healing.

**Correct Answer:** C.