**Core Concept**
Local anesthetics can be broadly classified into two categories: surface (or topical) anesthetics and injectable anesthetics. Surface anesthetics are applied directly to the skin or mucous membranes to produce local anesthesia, whereas injectable anesthetics are administered via injection into deeper tissues. The primary difference between these two categories lies in their lipid solubility and the mechanism by which they interact with nerve fibers.

**Why the Correct Answer is Right**
Bupivacaine is an amide-type local anesthetic that is primarily used for its injectable form, providing prolonged anesthesia after injection into deeper tissues. Its high lipid solubility allows it to penetrate nerve fibers more effectively, making it an ideal choice for regional anesthesia and nerve blocks. However, due to its high lipid solubility and potency, bupivacaine is not used as a surface anesthetic, as it can cause systemic toxicity and other adverse effects when applied topically.

**Why Each Wrong Option is Incorrect**
**Option A:** Lignocaine (lidocaine) is an amide-type local anesthetic that is commonly used as a surface anesthetic for topical application, particularly in the form of creams, gels, or sprays. Its moderate lipid solubility and rapid onset of action make it suitable for surface anesthesia.
**Option C:** Procaine is an ester-type local anesthetic that is also used as a surface anesthetic, although it is less potent and has a shorter duration of action compared to other local anesthetics. Its low lipid solubility makes it less effective as an injectable anesthetic.
**Option D:** Cinchocaine is another ester-type local anesthetic that is used for surface anesthesia, particularly in the form of creams or ointments. Its low potency and short duration of action make it less suitable for injectable forms of anesthesia.

**Clinical Pearl / High-Yield Fact**
When selecting a local anesthetic, consider the desired duration of action, potency, and the specific application site. Surface anesthetics like lignocaine and procaine are ideal for topical application, while injectable anesthetics like bupivacaine are better suited for deeper tissue anesthesia.

**✓ Correct Answer: B. Bupivacaine**