#help For Q.4 my initial logic translation was the contrapositive /RSVP -> /I because I interpreter as the invite (I) as the negate necessary. Subsequently, Rudy affirmed the sufficient which triggers the necessary condition (/I). Is this the correct approach? I am confused.

#help # confused I am confused about why the statement following unless (negate, sufficient) in the necessary condition. When I did the exercise, I focused on the unless but placed this statement in the sufficient part of the condition and negated it.