It looks like this question wants you to figure out your answer by looking at the chart to see if it looks reasonable.
The first answer doesn't seem to fit the plot so we know that, that inst right. The second one seems like it could work with the question but we dont have enough info to rule it in or out. The third one seems really off because alot of the dogs on the chart lived to be 14 if they where a good weight.
Answer 2: Dani doesn't remember Ol'Sniffy's age correctly, seem like the best fit.
Hope this helped!