Given the question: Many areas of cropland in Bangladesh are becoming unfit for farming. The land is becoming salty. It is a big problem for the small country which has more than 155 million people because growing crops is the most common way Bangladeshis support themselves. Farmers in the country are learning to grow vegetables in so-called "vertical gardens. " The soil in these gardens is better because heavy rains have removed much of the salt. Shobitha Debna is a 35-year-old farmer in the village Chandipur is able to grow hundreds of kilograms of vegetables each season in her small garden. This kind of farming is new in Chandipur. But it may spread across the country.Most of Bangladesh is at or below sea level. Rising seawaters linked to climate change has severely affected the country. High water from storms in coastal areas also add salt to soil. High salt content makes crops less productive. The salty sea water flows into rivers, which then flood Chandipur and other villages. Vegetable crops fail. For three years now, hundreds of villagers have grown crops in vertical gardens. From July to October, about l. 5 meters of rain falls in Bangladesh. The seasonal rains remove salt from the soil. At the end of the rainy season, villagers collect the cleaned soil and place it in large containers. They use that soil to grow vegetables. WorldFish Center, a non-profit International group has trained about 200 villagers in southwestern Bangladesh to make vertical gardens. Over the next two years, the center will train about 5,000 people. A vertical garden is easy to make. Villagers fill containers with good soil and natural fertilizers. They put the containers on bricks so they are off the ground. They add pieces of the bricks to the soil to help water flow and drain. Villagers also grow vegetables in containers made from large, thin pieces of plastic supported by bamboo. This is called "vertical tower" which can produce more than 100 kilograms of vegetables each. The main idea of this passage should be_. A) Poor country, rich people B) A non-profit group's help C) Salty soil, high yield D) Creative methods to grow crops
The answer is:
A