【单选题】
设论域为整数集，下列真值为真的公式是（ ）
①
<imgwidth="116"height="20"src="../uploadfiles/word/lsss001.files/image023.png">
②
<imgwidth="116"height="20"src="../uploadfiles/word/lsss001.files/image024.png">
③
<imgwidth="119"height="20"src="../uploadfiles/word/lsss001.files/image025.png">
④
<imgwidth="134"height="20"src="../uploadfiles/word/lsss001.files/image026.png">