【正确答案】 C

【答案解析】原文：The amount of plastic waste flowing into the ocean could triple in 20 years unless businesses and governments act to reduce plastic production.That warning comes from a new study that appeared recently in the publication Science.The study, called “Breaking the Plastic Wave”, identified measures that could reduce plastic pollution that gets into the ocean by 80 percent.If no action is taken，however，the amount of plastic going into the sea every year will rise from 11 million metric tons to 29 million metric tons by 2040，the study said.根据新闻定位句可知,许多品牌正在尽一切可能确保货架上的商品充足，但同时也指出,购买超过需求的商品有时可能意味着其他商品会缺货。因此，信息发布的目的是劝说购物者不要购买超出他们需要的东西。故选C。