What does “it” refer to in the second paragraph?

参考解析：

推理判断题。根据第二段最后两句“The second kind, situational loneliness, is a natural result of a particular situation—for example, a family problems, the death of a loved one, or moving to a new place. Although this kind of loneliness can cause physical problem, such as headaches and sleeplessness, it usually does not last for more than a year.”可知，第二种是情境性孤独，是特定情况下的自然结果——例如，家庭问题、亲人去世或搬到新地方。虽然这种孤独会导致身体问题，比如头痛和失眠，但通常不会持续超过一年。由此可知，这两句介绍的是situational loneliness，第二句中的it和从句中的this kind of loneliness都指代的是situational loneliness。故选C。