## **Core Concept**
The question describes a classic presentation of a metabolic disorder in a newborn. The key features include refusal of breast milk, acceptance of glucose-water, vomiting, severe jaundice, positive Benedict's test (indicating reducing substances in the urine), and low blood glucose. These symptoms point towards a disorder of carbohydrate metabolism.

## **Why the Correct Answer is Right**
The symptoms described are characteristic of **Galactosemia**, a condition caused by the deficiency of enzymes required for galactose metabolism. The most common form is due to the deficiency of **galactose-1-phosphate uridyltransferase** (GALT). Normally, lactose in breast milk is broken down into glucose and galactose. In galactosemia, the inability to metabolize galactose leads to its accumulation, causing toxicity. The presence of reducing substances in the urine (positive Benedict's test) in the context of low blood glucose and the clinical presentation is highly suggestive of galactosemia.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but based on the context, we can infer that the correct answer involves an enzyme related to carbohydrate metabolism.
- **Option B:** Similarly, without the specific details of Option B, we focus on the correctness of Option C.
- **Option D:** This option is also not detailed, but given the context, it's clear that the correct answer relates to a specific enzyme deficiency.

## **Clinical Pearl / High-Yield Fact**
A critical clinical pearl is that **galactosemia** presents with symptoms shortly after birth, particularly after the introduction of lactose-containing feeds. A key feature is the presence of **reducing substances in the urine**, which can be detected by Benedict's test. Early diagnosis and dietary restriction of galactose-containing foods are crucial to prevent long-term complications such as developmental delay and liver dysfunction.

## **Correct Answer:** C. Galactose-1-phosphate uridyltransferase.