Final answer:
Option D, Antibody mediated complement activation, is not entirely a response of the innate immune system as it involves antibodies and is part of the adaptive immune response, unlike the other options which are direct innate immune responses.
Step-by-step explanation:
The question asks which of the following is NOT entirely a response of the innate immune system. The innate immune system includes various mechanisms and cells that provide an immediate response to a broad range of pathogens. This includes phagocytosis by macrophages, skin acting as a physical barrier, low pH in the stomach, and the production of antimicrobial peptides such as defensin.
The option that is NOT solely a response of the innate immune system is D. Antibody mediated complement activation. While complement activation is a part of the innate immune system, the classical pathway of complement activation requires antibodies which are produced by B cells and is therefore part of the adaptive immune response. It involves the specific recognition of pathogens, which is not a characteristic of the innate immune system. Therefore, answer D is the correct choice, as it involves processes of the adaptive immune system.