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：C。根据题干中的problem和classes go online可定位至倒数第二段。该段主要是说在线课程需要的条件及可能的问题，第一句说在线课程需要台式电脑或笔记本电脑，以及稳定可靠的网络。第二句说到，不是所有的学生都能获得这些资源，一些学生可能会处于不利地位。也就是说有些学生可能会因为没有这些资源而难以参加在线课程。C项与此内容相符，故为正确答案。 

错项排除：A项的be absent from在原文中无依据，故排除。B项利用倒数第二段中出现的a reliable internet connection进行干扰，但原文并没有说老师会担心网络问题，故排除。D项利用倒数第二段最后一句的resources和at a disadvantage进行拼凑，但原文是在说学生，并非学校，故排除。