**Core Concept**
The complement system is a group of proteins that play a crucial role in the innate immune response, helping to eliminate pathogens from the body. It is a cascade of reactions that ultimately lead to the destruction of pathogens through mechanisms such as opsonization, lysis, and inflammation.

**Why the Correct Answer is Right**
The complement system consists of three pathways: the classical pathway, the lectin pathway, and the alternative pathway. These pathways converge at the formation of C3 convertase, which cleaves C3 into C3a and C3b. C3b then binds to the pathogen, marking it for destruction through opsonization. The activation of the complement system also leads to the formation of the membrane attack complex (MAC), which creates pores in the pathogen's membrane, ultimately leading to its lysis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the complement system does not primarily function through the activation of neutrophils and macrophages. While these cells do play a role in the complement response, the system's primary mechanism is through the direct destruction of pathogens.
**Option B:** This option is incorrect because the complement system is not primarily involved in the production of antibodies. While the classical pathway is activated by antibodies, the system's primary function is through the direct destruction of pathogens.
**Option C:** This option is incorrect because the complement system is not primarily involved in the activation of T-cells. While the complement system can activate T-cells indirectly through the presentation of antigens, its primary function is through the direct destruction of pathogens.
**Option D:** This option is incorrect because the complement system is not primarily involved in the activation of B-cells. While the complement system can activate B-cells indirectly through the presentation of antigens, its primary function is through the direct destruction of pathogens.

**Clinical Pearl / High-Yield Fact**
The complement system plays a crucial role in the prevention of bacterial infections, particularly those caused by Neisseria species. Deficiencies in the complement system, such as C5 deficiency, can lead to increased susceptibility to these infections.

**Correct Answer: D. The complement system is not primarily involved in the activation of B-cells.**