c. Good!
This too is a likely possibility, which explains both the initial decrease
and the late increase in the vacuolar pH.
In addition, this hypothesis can also explain the changes
in vacuoles' size, also observed in this experiment (Fig.
1).
Keep this hypothesis in mind when we plan our next experiment.
Watch
an animation illustrating lysosomes fusion with phagosomes or defective
mitochondria.
Examine other possibilities 