**Core Concept**
Hemorrhagic disease of the newborn (HDN) is a condition characterized by bleeding due to vitamin K deficiency in newborns. Vitamin K is essential for the production of clotting factors in the liver, which are necessary for blood coagulation. The condition typically occurs within the first week of life.

**Why the Correct Answer is Right**
Vitamin K-dependent clotting factors, including prothrombin (factor II), factors VII, IX, and X, are necessary for the coagulation cascade. Newborns have low levels of these clotting factors because they have not yet synthesized sufficient amounts of vitamin K-dependent proteins. This deficiency leads to an increased risk of bleeding, particularly in the first week of life. Vitamin K administration at birth helps to prevent this condition by ensuring adequate production of clotting factors.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the core concept of hemorrhagic disease of the newborn.
**Option B:** This option is incorrect because it does not accurately describe a feature of HDN.
**Option C:** This option is not a recognized feature of HDN.

**Clinical Pearl / High-Yield Fact**
Newborns are at risk of bleeding due to vitamin K deficiency because they have not yet synthesized sufficient amounts of vitamin K-dependent clotting factors. Vitamin K administration at birth is essential to prevent this condition.

**Correct Answer: D.**