Need answer to Biology question, please?

C. This is actually what Pasteur proved using the s neck flask. Microorganisms travel via dust particles and would grow if the flask was open. However, in Pasteur's time, air was considered a vital force, that is, it had to be there for life to grow (which we now know to not be true), therefore, you can't simply cap off a vial because of course nothing would grow, there is no air! So if you filter the air, you are allowing air, but not bacteria into the broth and it would disprove spontaneous generation.