Final answer:
Increasing the activity of vesicular H+-ATPase would increase vesicle acidification.
Step-by-step explanation:
Vesicular H+-ATPase is an enzyme responsible for acidifying vesicles within cells. Therefore, increasing its activity would increase vesicle acidification.
This means that the concentration of hydrogen ions (H+) in the vesicles would increase. Higher acidification levels are important for various cellular processes, including the proper functioning of certain organelles and exocytosis.
Therefore, the correct answer is option b) Increase vesicle acidification.