eitijan wrote:Why option B is incorrect?

Since this question is about the two hypotheses, the first thing to do is to identify the hypotheses.

Hypothesis One: Tiger beetles cannot maintain their pace and must pause for rest.

Hypothesis Two: Tiger beetles cannot process visual information and so go blind and stop.

B says that beetles pause equally frequently whether the chase is up or down an incline.

- That they pause as much going when going downhill as they do when going uphill tends to undermine the hypothesis that they pause to rest, as it seems likely that they would need less rest when going downhill. Of course this conclusion is debatable, but that they go equally fast uphill and downhill does not strengthen either hypothesis.

B also says that the beetles immediately respond to changes in pursued insects' directions.

- That they change direction immediately tends to indicate that they see the insects clearly, undermining the hypothesis that the beetles cannot process the rapidly changing visual information. Also, in any case, that they rapidly change direction does not strengthen either hypothesis.

So since, if anything, B undermines both of the hypotheses, and since it strengthens neither, B is not the correct answer.