**Core Concept**
The Prothrombin Time (PT) is a measurement of the extrinsic coagulation pathway's efficiency, which is crucial for the formation of a blood clot. It assesses the time taken for blood to clot after adding tissue factor to the blood sample.

**Why the Correct Answer is Right**
The normal Prothrombin Time is approximately 11-14 seconds. This value is influenced by the levels of coagulation factors, particularly II, V, VII, X, and fibrinogen. The intrinsic coagulation pathway, which is measured by the Partial Thromboplastin Time (PTT), is also crucial in this process. The PT is a critical parameter in the diagnosis and management of coagulopathy.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not correspond to a specific time value. PT values can vary slightly depending on the laboratory and the method used, but a value is necessary to evaluate it.
* **Option B:** This option is incorrect because it is too long. PT values above 20 seconds are generally considered abnormal and may indicate a bleeding disorder or the presence of a coagulopathy.
* **Option C:** This option is incorrect because it is too short. PT values below 10 seconds may indicate an over-anticoagulated state or the presence of a coagulopathy.

**Clinical Pearl / High-Yield Fact**
Remember, PT is a critical parameter in the diagnosis and management of coagulopathy. A prolonged PT can be a sign of liver disease, vitamin K deficiency, or the use of certain medications such as warfarin.

**Correct Answer: D. 12 seconds**