Choice B rationale:

Clostridium tetani is responsible for tetanus. When a puncture wound is contaminated with spores of this bacterium, it can produce a potent neurotoxin that causes muscle contractions, rigidity, and potentially life-threatening complications.

Choice A rationale:

Clostridium difficile is not responsible for tetanus. It is a different bacterium that can cause gastrointestinal infections and antibiotic-associated diarrhea.

Choice C rationale:

Escherichia coli is not responsible for tetanus. While certain strains of

E. coli can cause food poisoning and other infections, it is not associated with tetanus.

Choice D rationale:

Streptococcus pneumoniae is not responsible for tetanus. It is a bacterium commonly associated with respiratory infections, such as pneumonia.