有组织预计金砖四国（不含南非）的GDP总量将从2008年占世界 份额的15%上升到2015年的22%，四国经济总量将超过美国。上述事实表明[ ]

A．国际政治经济新秩序发生了根本性变化

B．南北发展不平衡仍是全球最突出的问题

C．世界格局正向多极化演进

D．金砖四国为世界和平与安全做出了贡献

A farmer with 1,350 acres of land had planted his fields with corn, sugar cane, and tobacco in the ratio of 5:3:1, respectively, but he wanted to make more money, so he shifted the ratio to 2:4:3, respectively. How many more acres of land were planted with tobacco under the new system ？（）

A. 90

B. 150

C. 270

D. 300

E. 450