For this question, the correct answer is choice 2. While I've already known the meaning of "いいかげんにしなさい" is "enough!" and "act properly!", I still have no idea about the reason that choice 1 is incorrect.
I looked up for some example sentences of "えんりょ"
As what I know, both "しなさい" and "ください" have nearly the same meanings. (They just differ in the expressions and the strength of emotion.)
If "おタバコはご遠慮ください" is correct, then "おタバコはご遠慮しなさい" also seems to be correct for me.
Can anyone explain the usage of "遠慮" in details for me?