单选题：根据下列短文，回答题。Global Cancer Rates to Rise 50% by 2020The number

根据下列短文，回答题。Global Cancer Rates to Rise 50% by 2020
The number of new cancer cases worldwide is expected to increase by 50% by the year 2020. But a new report suggests that as many as a third of new cancers could be avoided by adopting healthier lifestyles and through public health action.
The World Cancer Report, released by the International Agency for Research on Cancer(IARC, part of the World Health Organization), shows that cancer has now emerged as a major public health threat in developing countries s well as affluent ones.
Overall, cancer was responsible for 12% of all deaths in 2000. But in many countries more than a quarter of all deaths are caused by cancer.
The report show that 10 million new cancers were diagnosed globally in 2000, and that number is expected to rise to 15 million by 2020. researchers say most of that increase will mainly be due to steadily aging population in both developed and developing countries and current trends in smoking and other unhealthy habits.
“Cancer has emerged as a major public health problem in developing countries for th3e first time, matching its effect in industrialized countries,” says researcher Paul Kleihues, MD, director of LARC, in a news release. “Once considered a 'Western' disease, the Report highlights that more than 50 percent of the world's cancer burden, in terms of both numbers of cases and deaths, already occurs in developing countries.”
The risk of being diagnosed with cancer in developed countries is double that in less-developed ones. However, the risk of dying from cancer is much higher in developing countries, where 80% cancer patients already have late-stage incurable tumors at the time of diagnosis.
Researchers say cancer rates have traditionally been higher in developed countries due to greater exposure to tobacco, occupational carcinogens, and an unhealthy Western diet and lifestyle. As less-developed countries become industrialized and more prosperous, they tend to adopt the high-fat diet and low physical activity levels typically seen in the West, which increase cancer rates.According to a new report, healthier lifestyles and pubic health action could help reduce about ___________. A．A　50% of new cancers
B．B　33% of new cancers
C．C　12% of new cancers
D．D　80% of new cancers