They give two things that are true of ALL immoral actions, the first being a conditional but the second isn't - which means all immoral actions have to be accompanied by feelings of guilt.
The questions stem asks which must be FALSE, so in (A), they say "some immoral actions...are not accompanied by feelings of guilt" which is a direct contradiction of what was said, so this has to be false. When I did this question, I saw the stuff in the middle ("that are not performed in public") as irrelevant and there to distract you. You can't have SOME immoral actions that aren't accompanied by feelings of guilt because we know all of them are.