A、In 86 years. B、In 50 years. C、In 25 years. D、In 20 years. C原文中提到，按照现有财富的增速，再过25年，当比尔. 盖茨86岁的时候，世界将诞生第一位万亿富翁。因此答案为C。

In our lifetimes, we could see the first trillionaire. And, most likely, that first trillionaire would be Microsoft co-founder Bill Gates. That’s according to research by Oxfam, an international network of organizations collectively working to alleviate global poverty. Its recently published report finds that eight billionaires from around the globe have as much money as the 3. 6 billion people who make up the poorest half of the world’s population. The report also finds that, given the faster growth of existing wealth, the world could have its first trillionaire in the next 25 years, when Gates would be 86.
    When Gates left Microsoft in 2006, his net worth was $50 billion, according to Oxfam. "By 2016, his wealth had increased to $75 billion, despite his commendable attempts to give it away through his Foundation, " the report says.
    In addition to the charitable work Gates does through his personal foundation, he is one of the founding members of The Giving Pledge, a commitment from some of the richest individuals in the world to give away more than half of their wealth.
    Oxfam researchers apply the average rate of growth the ultra-rich have been enjoying, 11％ per year since 2009, to Gates’ current levels of wealth (over $84 billion, according to Forbes). If his investments keep doing as well as they have been, the 61-yearcold Gates could indeed become the world’s first trillionaire.
    "In such an environment, if you are already rich, you have to try hard not to keep getting a lot richer, " Oxfam notes.
    Questions 9 to 11 are based on the passage you have just heard.
    9. What has Oxfam found recently?
    10. When will the world probably witness the first trillionaire?
    11. What does The Giving Pledge commit some of the richest individuals in the world to do?