Which statement best expresses a fundamental difference between the AICPA Code of Professional Conduct $($the AICPA code$)$ and the International Code of Ethics for Professional Accountants, including International Independence Standards, $($international code$)$ with respect to clients that are public interest entities $($PIEs$)?$

$1-$ Rules in the international code for PIEs are presented separately from the rules for other types of clients

$2-$ the AICPA code does not refer to PIEs in its interpretations or the conceptual framework

$3-$ the international code does not refer to PIEs in its provisions or the conceptual framework

$4-$ rules in the AICPA code for PIEs are presented separately from the rules for other types of clients