Colonies of the Bacterium Serratia Marcescens Are Red When Incubated at 22°C

Multiple Choice

Colonies of the bacterium Serratia marcescens are red when incubated at 22°C but white when incubated at 37°C. This is an example of 

A) antigenic variation.
B) genotypic change.
C) phenotypic change.
D) mutation.
E) selective media.