Answer:
B: I saw it an hour ago and I didn't want to answer because there are too many ifs. I tried, but it could be wrong.
Explanation:
This is not as simple as it sounds and I have a feeling that the correct answer is in the head of the person designing the question. In other words, I could easily get it wrong.
It depends on whether the tide is going in or going out to start with. The question would be a whole lot easier if the bottle was dropped miles from shore.
A: The bottle is capped. A is certainly not true. The low density of the bottle will keep it afloat until something happens that determines it's permanent direction. Not A.
B: It will if nothing else influences it. There will always be waves around that will insure an up and down movement. This is a possible answer, but not a certain one. A five year old could not throw it very far to start with. Let's read the rest.
C: Maybe. It has happened. The bottle needs a good start and the tide going out to happen. Let's read the last 2.
D: Not in a million. Not D.
E: It won't be still. The ocean is always moving. Not E.
I'm going to pick B, but it is not a slam dunk.