I didn't even realize they were only comparing elderly people. I choose B because being young doesn't necessarily mean you're more healthy. Perhaps all the young people have cancer and all the old people go to the gym everyday.

I think my Proctor was not a real person but a robot. I started with a real human but transferred to something named "something3-Watcher". Is it even possible to get a robot as a proctor?

You are confusing the concept of a control group and a control variable. This is an observational study, not an experiment.