Ineed to know the answer to the question

I would go with A. An Observation. Because he's looking at visual differences, for example: "based on smell, color change, and release of bubbles.

Question was not very clear if there are specific answer choices tell me and i'll try to you more. hope this though2 laps is 1 min. we know that for each min she does two times the amount of laps. for 12 laps we can do 12/2 which does give us 12 laps in 6 mins not 16 mins.