Hi p.arya,
No, wearing seat belts would not be considered to fall under basic driving skills. As Jon mentions in his earlier post (Post #3), wearing a seat belt would not be considered part of basic driving skills anymore than wearing a life vest would be considered to fall under basic swimming skills.
Another detail in Answer B worth noting is that both teenage drivers
and their passengers are less likely to wear seat belts.
Also, it's worth noting that this question originally appeared on the Oct. 1997 LSAT and may have been written some years before that. Seat belt use wasn't necessarily as prevalent then as it is now. (For example, an article that I just found states that seat belt use in 2021 is 55.9% greater than in 1994. Here's a link in case you're interested.)
https://tpmblegal.com/how-seatbelt-use-has-changed/
It's important to remember that certain practices/views that we take for granted today weren't always the norm, sort of like reading about how doctors used to recommend cigarettes back in the good old days.