All of the Following Are Aspects of Pasteur's Experiments to Disprove

Multiple Choice

All of the following are aspects of Pasteur's experiments to disprove spontaneous generation EXCEPT:

A) he boiled the infusions to kill any microbes present.
B) the flasks he used were sealed with corks.
C) the flasks were free of microbes until they were opened.
D) the necks of the flasks he used were bent into an S shape.
E) the flasks were incubated for very long periods of time.