The correct option is A Paramecium bursaria
Symbiosis is a relation between two organisms where both the partner are benefitted by the relationship. Paramecium bursaria is a species of ciliate protozoan that has a mutualistic symbiotic relationship with green algae called as Zoochlorella. The algae live inside the paramecium which provides movement, protection and in turn algae provide it with food. Thus, the correct answer is option A.