I picked c. I didn't realize that we know he wasn't already running late, since he came "a few minutes late" which is less than 15 minutes.

@Robert Carlson the large gatherings could have been cancelled because people were sick and didn't go out to create the gathering. Even though we have to add in an assumption that people got sick, we also have to add in an assumption to a, that they didn't make a new medicine.

Doesn't this strengthen the argument? The argument says watching yourself makes you more motivated than watching others. The twin study shows that watching someone else (even someone who looks like you) makes you overreport how much you did that activity. Therefore, in the exercise study, the second group overreported their exercise amount - meaning they actually exercised even less than they claimed. This would make the gap between the groups even larger, strengthening the conclusion.

The tiger argument is missing the premise that aggressive animals aren't suitable as pets