Why doesn't an exchange between sister chromatids result in the production of a recombinant?

A) Sister chromatids are genetically identical and therefore an exchange would not show any change in phenotype
B) Sister chromatids are not genetically identical and therefore cannot exchange information
C) Sister chromatids are genetically identical and therefore cannot exchange information
D) Sister chromatids are not genetically identical and therefore an exchange would not show any change in phenotype
E) None of these explains this