Question: How many Grand Slam singles championships were won by the winner of the 1974 Virginia Slims of Newport?
Sentence (from "1974 Virginia Slims of Philadelphia"): The 1974 Virginia Slims of Philadelphia was a women's tennis tournament played on indoor carpet courts at the Palestra in Philadelphia, Pennsylvania in the United States that was part of the 1974 Virginia Slims World Championship Series.
Relevant evidence: No