**Core Concept**
Clostridium tetani is a gram-positive, rod-shaped bacterium that produces a distinctive toxin responsible for tetanus infection. The characteristic shape of the bacterium is crucial for its identification under the microscope.

**Why the Correct Answer is Right**
The correct answer describes Clostridium tetani as having a "chain of spores" appearance. This is due to the presence of terminal spores that are highly resistant to environmental stressors. The bacterium's ability to form chains is a result of the cells dividing in a linear fashion, with each cell producing a terminal spore. This unique feature allows for the identification of C. tetani on a stained slide.

**Why Each Wrong Option is Incorrect**
**Option A:** "Bipolar staining" is incorrect because while C. tetani does have terminal spores, it does not exhibit bipolar staining like some other bacteria.
**Option B:** "Club-shaped" is incorrect because C. tetani is not characterized by a club-shaped morphology.
**Option C:** "V-shaped" is incorrect because C. tetani does not have a V-shaped appearance.

**Clinical Pearl / High-Yield Fact**
The terminal spores of C. tetani are highly resistant to environmental stressors and require specific conditions to germinate. This unique feature allows the bacterium to survive in a variety of environments, making it a significant public health concern.

**Correct Answer:** C. Club-shaped.