【单选题】
下列各图是无向完全图的是（ ）
①
<imgwidth="27"height="84"src="../uploadfiles/word/lsss001.files/image042.png">
②
<imgwidth="86"height="90"src="../uploadfiles/word/lsss001.files/image043.png">
③
<imgwidth="92"height="84"src="../uploadfiles/word/lsss001.files/image044.png">
④
<imgwidth="96"height="78"src="../uploadfiles/word/lsss001.files/image045.png">