FCESP Question #77: Real Exam Question with Answer & Explanation

According to the Message Header printed below, which antispam technique detected this email as spam: Return-Path: [email protected] (SquirrelMail authenticated user user1) by 172.16.78.8 with HTTP; X-FEAS-HASH: 6ef419f0a0608b1655xxxxe68080df3cb12fc38f1118d2f085985eeb000274d7 Sat, 18 Apr 2009 15:53:06 +0200 (CEST) Message-ID : [email protected] Date : Sat, 18 Apr 2009 15 :53 :06 +0200 (CEST) Subject: [SPAM] Sales From: [email protected] To: [email protected] User-Agent: SquirrelMail/1.4.10a-1.fc6 MIME-Version : 1.0 Content-Type : text/plain ;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Original-To: [email protected] Delivered-To: [email protected] Received: from fm.sub.training1.lab (fm.sub.training1.lab [192.168.11.101]) by mail.training.lab (Postfix) with ESMTP id A9160187073 for [email protected]; Sun, 19 Apr 2009 16:58:48 +0200 (CEST) Received: from mail.external.lab ([172.16.78.8]) by fm.sub.training1.lab with ESMTP id n3LEPHWu001093 for [email protected]; Tue, 21 Apr 2009 10:25:17 -0400 Received: from 172.16.78.8 (localhost [127.0.0.1]) by mail.external.lab (Postfix) with ESMTP id 247D9BF893 for [email protected]; Sat, 18 Apr 2009 15:53:06 +0200 (CEST) Received: from 192.168.3.101