Final answer:
Determining if a bacterium is acid-fast is crucial for diagnosing diseases such as tuberculosis because it involves bacteria with a waxy cell wall that requires specific staining techniques. The correct option is c.
Step-by-step explanation:
The clinical significance of determining whether or not a bacterium is acid-fast primarily assists in the diagnosis of specific diseases, such as tuberculosis and leprosy, caused by acid-fast bacteria like Mycobacterium tuberculosis and Mycobacterium leprae. These bacteria have a unique cell wall structure with a waxy substance, mycolic acid, which prevents standard stains from penetrating. Consequently, the acid-fast staining technique, using the Ziehl-Neelsen or Kinyoun method, is necessary to visualize these organisms. A positive acid-fast stain is an important step in the diagnostic process and can lead to specific antibiotic treatments for these infections.