Answer:
The correct answer is "vacuole"
Step-by-step explanation:
The vacuole is an organelle found in most plant cells that serves to isolate substances that could be harmful for the cells and maintain pH equilibrium. Vacuoles have no particular form or shape, however they can be identified for looking like a bubble of considerable size. In the attached image it can be seen that the organelle labeled A corresponds to a vacuole for its size and bubble like form.