Answer: The market is weak form efficient
Step-by-step explanation:
Weak form markets are markets in which stocks are said to incorporate all past information in their prices. Investors who believe that the market is at weak form efficiency believe that since the stock contains past information, using the current information in the company's books to determine if the company is overvalued or undervalued is possible (fundamental analysis).
Warren Buffet's Value Investing means that he invests in stocks that he believes to be undervalued and sells them for higher or holds them when they appreciate. This is consistent with fundamental analysis. If Warren Buffet is beating the market by investing in undervalued stock then the market is indeed weak form efficient.