**Core Concept**
Lidocaine is a local anesthetic and antiarrhythmic medication that belongs to the class of amino amide-type local anesthetics. Its pKa value is critical in understanding its pharmacological properties, including its ability to cross cell membranes and bind to sodium channels.

**Why the Correct Answer is Right**
The pKa of lidocaine is approximately 7.9. This value is significant because it determines the proportion of the drug that is in its ionized (uncharged) form at physiological pH (around 7.4). At pH values below its pKa, lidocaine is predominantly ionized, whereas at pH values above its pKa, it is more likely to be in its non-ionized (charged) form. The non-ionized form of lidocaine can readily cross cell membranes, allowing it to exert its local anesthetic effects. The ionized form, on the other hand, is more water-soluble and less able to cross cell membranes.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** This option is not provided.
* **Option C:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
The pKa of a local anesthetic is a critical determinant of its potency and duration of action. A higher pKa value is associated with a more rapid onset of action but also a shorter duration of action.

**Correct Answer: B. 7.9**