Stocks tumbled Monday, sending the broad market to a three-month low, as investors caught “Enronitis.” The Dow Jones Industrial Average tumbled 220.17 points – or 2.22 percent – to 9,687.00 – its lowest close since Jan. 29. The Standard & Poor’s 500 Index lost 27.76 points (2.47 percent) to 1,094.44 – its lowest close since Nov. 2. The Nasdaq composite index fell 55.71points, or 2.91 percent, to 1,855.53 (2.91 percent) – it’s lowest close since Nov. 12.