@abedalsolaiman I had the same reasoning! If they're comparing this group of daily drinkers who have 3 glasses of wine to binge drinkers, who might be having 3+ glasses of vodka, obviously the health detriments in binge drinking don't apply to the daily drinkers. Being more likely to die from sudden heart attacks could be related more strongly to the type of liquor, not the frequency. I'm not too sure about why C is irrelevant either.

I imagined a dialogue to help me answer this question.

coach's team is loud and jeers at opponents when they win, parading about for a long time after the match has come to a close

Critic: Your team is a little too...enthusiastic when it comes to your wins. You're too loud and too mean to the opponents, and I feel like that's hurtful and unnecessary.

Coach: How dare you say my team is unprofessional! Say, even the top players are this loud and effusive! Let my players enjoy themselves!

Critic: Well, I didn't say you're unprofessional...just a little too much.

I wanted to share an example I used to illustrate the concept:

M -> N and O

I imagined M being "meal", and N being "noodles" and "O" onions. It is necessary to have noodles and onions to make a tasty pasta meal.

Clearly, if you're out of noodles, you can't make pasta, and if you're out of onions, it might turn out rather flavourless (not a meal). This logic translates pretty cleanly into:

/N or /O -> /M

Let me know if this helped anyone else!