Questions 1～5

I heard my train approaching. I ran up a two-story escalator and hopped on my train. I was relieved to make it onto my train, but my relief was short-lived-While catching my breath, I heard the announcement that the train would be stopped because of an accident. This was the same announcement I had heard just a week before. The number of train accidents is increasing in Japan, and it is thought that one-third of the accidents result from suicide attempts.
Japan’s suicide rate is one of the highest in the world. More than 30,000 Japanese people take their lives every year, even though Japan is one of the richest and the most advanced countries in the world today.
Allow me to describe some factors of the sickly Japanese situation and to list some silver bullets which might cure the illness. To find the causes of today’s Japanese social problems, I looked back at history and realized that the way Japan dealt with the aftermath of World War Ⅱ might have directly affected what Japanese society is today.
No other country except Japan could become a world leader just 20 to 30 years after losing a major war and achieve one of the world’s highest GNPs. It would have been impossible without Japanese diligence. While I am amazed at Japan’s development, I suspect that Japan also lost something important during the postwar boom era. Japan is the only country that has suffered from the damage inflicted by atomic bombs. However, the nuclear attack is just a half-century-old story for most people now. It seems that Japan moved too swiftly to put this pain behind us in order to grab immediate profits in business. While Japanese society has prospered, it has focused only on short-term gain. Therefore, it has neglected the dignity of human life.
Japanese seek material affluence and convenience, but in chasing these things, we have left behind richness of the mind and the heart. As a result of this, people in Japan have no dreams and hope. Our society has become a cold and lonely place, which lacks life and spirit.
How should Japanese society overcome its unhealthy situation When one does not do what one should do, he or she cannot come alive. It seems that Japan is in exactly the same situation. To make our society vigorous, Japan should carry out its duties and responsibilities. For example, it is the duty of Japan to proclaim the importance of world peace. It is the responsibility of Japan to share with the entire world the technology it has developed which might help prevent global warming. To have a true happy life, each of the people in Japan should rethink the value of life and the importance of caring for each other.
These things have been neglected because Japanese have been overzealous in their quest for money and material wealth. Only when Japanese people understand what true happiness is will Japanese society grasp the importance of human life.

The word "this" (para. 5, underlined. should refer to ______.

A. the postwar boom era
B. the pursuit of material affluence
C. the damage inflicted by atomic bombs
D. the loss of richness of the mind and the heart