Answer:
C.
Step-by-step explanation:
Why C?
It's because, to make bubbles, you usually need some form of gas like O2 aka Oxygen to make bubbles. Like if you blow into a straw, a straw thats in your dribk, it causes it to bubble up sometimes.
You can eliminate A.
Just because you drill into the ground, it doesnt cause gas. Unless it's to make a factory and causes polution by releaing chemicals into the air, the yes.
Eliminate D.
Because A doesn't seem right, it most likely not be all of them.
For B. I'm not sure
I'm not sure what Low Spots are unless you're talking about those small little holes made in the sand, it was mostly made by crabs
If I'm wrong, let me know. But, I hope this helped you! :)