**Core Concept**
The incubation period of a disease refers to the time elapsed between exposure to the pathogen and the onset of symptoms. Pertussis, also known as whooping cough, is a highly contagious respiratory tract infection caused by the bacterium *Bordetella pertussis*. Understanding the incubation period of pertussis is crucial for public health measures and timely diagnosis.

**Why the Correct Answer is Right**
The incubation period of pertussis typically ranges from 7 to 10 days, with a median of 7-8 days. This period is critical as it allows for early detection and isolation of infected individuals, thereby preventing further transmission. The bacterium *Bordetella pertussis* multiplies rapidly in the respiratory tract, leading to the release of toxins that cause the characteristic symptoms of whooping cough.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as the incubation period of pertussis is not typically less than 5 days.
* **Option B:** This option is incorrect as the incubation period of pertussis is not typically more than 14 days.
* **Option D:** This option is incorrect as the incubation period of pertussis is not typically more than 10 days.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the incubation period of pertussis can be shorter in individuals who have been previously vaccinated or have immunity from previous infections. This highlights the importance of maintaining up-to-date vaccination records and practicing good hygiene to prevent the spread of pertussis.

**Correct Answer:** C. 7-10 days