The Spontaneous Generation of Living Things from Nonliving Things Was

The spontaneous generation of living things from nonliving things was thought to be common many years ago. Louis Pasteur used specially constructed flasks with a long S-shaped neck to prove that

A) spontaneous generation of organisms occurred in broth in the flasks.
B) oxygen was required to have living things present in the broth.
C) microorganisms had to enter the flask to get the broth to "spoil."
D) the broth "spoiled" even if organisms were not present.