**Core Concept:** PTT (Partial Thromboplastin Time) is a coagulation test that assesses intrinsic pathway function, while PT (Prothrombin Time) is an overall coagulation test that measures extrinsic, common, and intrinsic pathways. Prolonged PT indicates impaired extrinsic pathway function, while normal PTT suggests normal intrinsic pathway function.

**Why the Correct Answer is Right:** A normal PTT indicates that the intrinsic pathway is functioning normally, which is crucial for blood clotting. If the intrinsic pathway is not affected, the result indicates that the other factors involved in clotting (extrinsic pathway) are functioning correctly. This combination of normal PTT and prolonged PT suggests that the issue lies within the extrinsic pathway, most likely due to a deficiency of factors II, VII, IX, or X.

**Why Each Wrong Option is Incorrect:**

A. **Option C (Normal PTT and Prolonged PTT):** A normal PTT along with prolonged PT indicates impaired extrinsic pathway function, not normal intrinsic pathway function.
B. **Option D (Normal PTT and Shortened PTT):** A normal PTT combined with shortened PTT is possible, but it indicates a deficiency in factors II, VII, IX, or X, not specifically intrinsic pathway dysfunction.

**Why the Correct Answer is Right:**

This combination of findings suggests a deficiency in factors II, VII, IX, or X, which are part of the extrinsic coagulation cascade. These factors are involved in the extrinsic pathway, which is distinct from the intrinsic pathway. When these factors are deficient, the extrinsic pathway will be impaired, leading to prolonged PT and normal PTT.

**Clinical Pearl / High-Yield Fact:** Prolonged PT and normal PTT can be seen in vitamin K deficiency, as vitamin K is essential for the synthesis of these extrinsic pathway factors. In cases of vitamin K deficiency, the extrinsic pathway is impaired, causing prolonged PT and normal PTT.