COLUMBIA, S.C. -- The mystery surrounding the $1.5 billion Mega Millions jackpot from last October is partly over as lottery officials announced Monday that a South Carolina resident had stepped forward to claim the prize but elected to remain anonymous.A lottery commission statement said the person submitting the claim for what was the second-largest lottery in U.S. history has chosen the cash option, a one-time payment of nearly $878,000,000. That's the largest jackpot payout to a single winner in United States history, it said."We are delighted that the winner is a South Carolinian and has come forward to claim this remarkable prize," said Hogan Brown, the Commission's Executive Director.The winning ticket was sold between Oct. 20 and Oct. 23 of last year at a convenience store in Simpsonville, a suburb of the South Carolina city of Greenville.For months, South Carolina residents had speculated on why the winner hadn't stepped forward.Some theorized that the winner was on the run from police and feared a background check if he or she won. Some thought the winner was so overwhelmed at seeing the winning numbers pop up that he or she died on the spot. Others speculated that the winning ticket had been purchased by an office pool and was now the subject of litigation.The winner had until April 19 to claim the prize. The statement Monday gave no clue as to why the winner took his or her time to come forward.The prize being claimed does come with other benefits for the state and the shop that sold it.The KC Mart in Simpsonville will receive $50,000 for selling the winning ticket and the state will receive $61 million in income taxes from the winner, the commission said in the statement.