Which of the Following Was NOT an Aspect of Pasteur's

Multiple Choice

Which of the following was NOT an aspect of Pasteur's experiments to disprove spontaneous generation?

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