**Core Concept**
Tetanus infection predominantly occurs through Clostridium tetani spores entering the body through wounds contaminated with soil, dust, or faecal matter. The bacteria thrive in environments with low oxygen levels and produce tetanospasmin, a potent neurotoxin responsible for the disease's characteristic muscle spasms.

**Why the Correct Answer is Right**
Wounds contaminated with faecal matter are more likely to develop tetanus due to the presence of C. tetani spores. When these spores enter the body, they germinate into vegetative cells, which produce tetanospasmin. Tetanospasmin then travels to the central nervous system, where it blocks the release of neurotransmitters, leading to muscle rigidity, spasms, and eventually, respiratory failure. The risk of tetanus is higher in wounds contaminated with faecal matter because the spores are more likely to be present in this type of environment.

**Why Each Wrong Option is Incorrect**
**Option A:** Burn cases are not typically associated with tetanus, as the bacteria require a moist environment to grow, and burns usually have a low bacterial load.
**Option C:** Open fractures increase the risk of various infections, but tetanus is not as common as other infections in this context, as the bacteria require a specific environment to grow.
**Option D:** Gunshot wounds can be contaminated with a variety of bacteria, but the risk of tetanus is not as high as in wounds contaminated with faecal matter.

**Clinical Pearl / High-Yield Fact**
Tetanus is often referred to as "lockjaw" due to the characteristic jaw spasms that occur in patients with the disease. This term is a useful reminder of the condition's clinical presentation.

**✓ Correct Answer: B. Wounds contaminated with faecal matter**