**Core Concept**
The concept of carriers in microbiology refers to individuals who harbor and transport pathogens without displaying any symptoms themselves, but can potentially spread the disease to others. This phenomenon is crucial in understanding the epidemiology of infectious diseases.

**Why the Correct Answer is Right**
Carriers play a significant role in the transmission of diseases such as typhoid, cholera, and streptococcal infections. They can be asymptomatic carriers, where the pathogen is present in their bodily fluids, or symptomatic carriers, where they exhibit mild or atypical symptoms. In both cases, carriers can serve as a source of infection for others, highlighting the importance of identifying and isolating them to prevent disease spread.

**Why Each Wrong Option is Incorrect**
* **Option A:**
* **Option B:**
* **Option C:**
* **Option D:**

**Clinical Pearl / High-Yield Fact**
It's essential to note that asymptomatic carriers can be more challenging to identify, and their presence can lead to the spread of disease in the community. In cases like typhoid, carriers can remain asymptomatic for years, emphasizing the need for regular screening and surveillance.

**Correct Answer: C.