Which Scenario Provides Evidence for Endosymbiosis in a Modern Day

Which scenario provides evidence for endosymbiosis in a modern day experiment?

A) antibiotic sensitive bacteria can internalize in an amoeba,which is then also killed after antibiotic treatment
B) antibiotic sensitive bacteria cannnot internalize in an amoeba
C) antibiotic sensitive bacteria can internalize in an amoeba,which is not killed after antibiotic treatment
D) antibiotic sensitive bacteria can internalize in an amoeba,but the amoeba then dies
E) all scenarios are equally inconsistent with the endosymbiont theory