**Core Concept:** Mosquito control is a crucial aspect of public health, particularly in reducing the transmission of vector-borne diseases like malaria, dengue, and filariasis. Mosquitoes are primarily controlled through biological, chemical, and physical methods. Biological control involves the introduction of natural predators or parasites to regulate mosquito populations. Chemical control includes the use of insecticides and larvicides.

**Why the Correct Answer is Right:** Larvicides are substances applied to mosquito breeding sites (e.g., ponds and wells) to kill mosquito larvae and prevent their development into adult mosquitoes. In this question, the correct answer refers to a chemical method for mosquito control.

**Why Each Wrong Option is Incorrect:**

A. **Option A (Natural predators or parasites):** While natural predators and parasites are used in biological control, they are not the primary method for controlling mosquitoes in water bodies.

B. **Option B (Physical methods):** Physical methods involve barriers like screens and nets, which are used to prevent mosquito bites but not to directly control mosquito populations in water bodies.

C. **Option C (Pesticides):** Pesticides are toxic substances used to control insects, including mosquitoes. However, they are not specifically designed for mosquito larvae control and may harm other aquatic organisms and the environment.

D. **Option D (Larvicides):** Larvicides are substances applied to breeding sites to target mosquito larvae, therefore preventing their development into adult mosquitoes and reducing mosquito populations. Larvicides are a targeted and environmentally friendly approach compared to other control methods.

**Clinical Pearl:** Larvicides, such as Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus, are often used for mosquito control in water bodies. They are environmentally friendly, non-toxic to mammals, and target mosquito larvae specifically.

In summary, the correct answer (D) refers to larvicides, which are substances used to control mosquito populations in water bodies. Larvicides are environmentally friendly and effective in reducing mosquito populations, making them the optimal choice for mosquito control in comparison to other control methods.