A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium. Following incubation, only the E. coli grows in the culture. What is the most likely explanation?
a) Staphylococcus epidermidis is gram-positive.
b) Escherichia coli is a facultative anaerobe.
c) Staphylococcus epidermidis is a mesophile.
d) Escherichia coli is more fastidious.