Answer: C. Opacity
Step-by-step explanation:
When an object has translucency, we can see through it slightly and see light coming through it, but cannot clearly see all the way through it.
When an object has transparency, it is completely see-through.
When an object has opacity, we cannot see through it at all.
The circled portion of the bottle represents opacity. We cannot see through the cap, so the correct answer is option C.