What did Warren Buffett tell his wife to invest in?

In a recent interview, Warren Buffett, the renowned investor and chairman of Berkshire Hathaway, was asked about his investment advice for his wife. With a characteristic twinkle in his eye, he replied, "My wife has a very simple investment strategy. I told her to put all her money in an index fund and forget about it. I believe that over time, the market will outperform most managed funds, and the simplicity of this approach will allow her to avoid the pitfalls of chasing hot investments or trying to time the market." This advice, while straightforward, highlights Buffett's belief in the power of diversification and the long-term benefits of passive investing.