The correct answer is Antoni van Leeuwenhoek.

Antoni van Leeuwenhoek (1632-1723) was a Dutch scientist, known as the "Father of Microbiology," primarily because of his pioneering work in microscopy. Unlike other scientists of his time, Leeuwenhoek didn't just improve existing microscope designs; he crafted his own, remarkably powerful single-lens microscopes. These microscopes, although simple in design compared to modern compound microscopes, allowed him to achieve magnifications far exceeding those of his contemporaries. This groundbreaking technological advancement enabled Leeuwenhoek to make groundbreaking discoveries.

His meticulous observations using these homemade microscopes led to the discovery of a whole new world of microorganisms, previously unseen by the human eye. He meticulously documented his findings, providing detailed descriptions of bacteria, protozoa, and other single-celled organisms. This was a monumental contribution to science, laying the foundation for the field of microbiology. Leeuwenhoek's work revolutionized our understanding of life, revealing the vast complexity and diversity of microbial life present everywhere in the environment. He even observed and described human blood cells, spermatozoa, and muscle fibers; all achieved with his innovative microscope. His discoveries were not immediately accepted universally, but his perseverance and detailed observations eventually earned him scientific recognition and he is rightly regarded as the founder of microbiology.