**Core Concept**
The question is referring to the levels of prevention in public health, which include primary, secondary, and tertiary prevention. The correct answer is related to the promotion of healthy behaviors and disease prevention through environmental modifications.

**Why the Correct Answer is Right**
The installation and usage of sanitary latrines by the general public is an example of primary prevention. This is because it aims to prevent the occurrence of diseases such as diarrhea, cholera, and typhoid fever by reducing the transmission of pathogens through contaminated feces. Sanitary latrines help to contain human waste, preventing it from entering the environment and contaminating water sources. This measure is particularly effective in low-income settings where access to modern sanitation facilities is limited.

**Why Each Wrong Option is Incorrect**
**Option A:** Secondary prevention is focused on early detection and treatment of diseases, which is not the primary goal of installing sanitary latrines. While latrines may help to reduce the incidence of certain diseases, they do not provide a mechanism for early detection or treatment.

**Option B:** Tertiary prevention is aimed at reducing the impact of established diseases, which is not relevant to the installation and usage of sanitary latrines. Latrines are a preventive measure, not a treatment for existing diseases.

**Option C:** This option is not a recognized level of prevention in public health, and it is not relevant to the context of the question.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the installation and usage of sanitary latrines are critical components of primary prevention, particularly in low-resource settings. This measure can significantly reduce the burden of waterborne diseases and improve public health outcomes.

**Correct Answer:** C. Primary prevention