Online classes began to be popularized just a few decades ago. They are advertised as a way for adults to finish their education and students to learn the material at their own pace—it is far more compatible for people with busy schedules.

        But after being enrolled in an online course last fall semester, I came to realize online classes were merely a means to fulfil course requirements.

         First of all, students lack the desire to learn, and they simply complete their assignments to receive credit for a passing grade rather than genuinely engage with the course material.

        As online courses tend to have more than 100 students, most of the assignments are short and simple. They are not designed for students to interact with the material in depth but designed to be graded easily to accommodate such a large number of students.

         Perhaps the biggest disadvantage of taking an online class is the absence of face-to-face interaction between the teacher and their students. Live sessions are infrequent and are often scheduled during the middle of the day when students have to attend other classes or work. The office hours of the professor may also be during inconvenient times for many students as well. Most interaction with the professor has to be through email which is often impersonal. It is nearly impossible for students to build a relationship with their professor.

        There is also little interaction amongst students. It can be harder for students to create study groups and form relationships with their peers.

        Online classes also require either a computer or laptop and a reliable internet connection. Not all students have access to these types of resources, whether it is for financial or other reasons, and some students can be put at a disadvantage.

        Offering online classes certainly helps students who would otherwise not be able to attend classroom sessions. However, they fail to provide a genuine education with an emphasis on convenience rather than critical thinking. We need restructured online classes in which students can have a learning experience that will actually provide quality education.

解析：A。根据题目中的online course assignments可定位至原文第四段。该段第一句提到，由于参加在线课程的学生往往超过100人，所以大多数作业都量少而简单。第二句接着说到，这些在线课程作业的目的不是为了让学生与课程资料进行深度互动，而是为照顾到如此庞大的学生人数，方便打分。A项与此内容相符，其中的made convenient to mark是对第二句中designed to be graded easily的同义替换，故正确答案为A。  

错项排除：第四段提到，在线课程作业的目的不是为了让学生与课程资料进行深度互动，B项与此内容相悖，故排除。C项利用原文中的material和access进行干扰，但原文是说不是所有学生都能获得这些资源，并不是课程资料容易获得，故C项排除。D项利用原文第四段第二句中的accommodate进行干扰，但原文是说照顾到如此庞大的在线学生人数，而不是满足学生的需求，故D项排除。