By Dan Weil The S&P 500 Information Technology index has dropped 15% in the past three months and 28% year to date. Most big technology stocks tumbled after their third quarter earnings reports, adding to the losses they already had suffered this year. But that helps make at least three of them attractive as long-term buying opportunities, according to Morningstar: Alphabet (GOOGL) – Get Alphabet Inc. Report, Amazon.com (AMZN) – Get Amazon.com Inc. Report, and Microsoft (MSFT) – Get Microsoft Corporation Report. Morningstar’s Take on AlphabetMorningstar analyst Ali Mogharabi assigns the compan…