What Was the Important Contribution to Microbiology Made by Anton

What was the important contribution to microbiology made by Anton Van Leeuwenhoek in the 1600s?

A) He invented the microscope.
B) He was the first to observe microorganisms.
C) He disproved spontaneous generation.
D) He was the first to show that a disease could be caused by a microorganism.
E) He was the first to describe fermentation.