SIMPSONVILLE, S.C. (AP) — Nearly everyone in this small South Carolina town has a theory for the city’s billion-dollar mystery: Who won the $1.5 billion Mega Millions jackpot announced last October? Maybe the winner was so overwhelmed upon seeing the winning numbers that she or he died on the spot? Maybe the winner is on the run from police and fears a background check? Maybe that winning ticket fell from a car visor, ended up in a trash can and is forever buried at the Twin Chimneys Landfill. Or maybe, the winner is still going on with life as usual, before quietly taking the $878 million lump sum. With less than two months to go, the clock is ticking. Whoever won the second largest lottery in U.S. history has until 5 p.m. on April 19 to walk into the South Carolina Lottery office in Columbia with the signed ticket and claim the jackpot. The winning ticket was sold at the KC Mart in Simpsonville sometime between Oct. 20 and the drawing at 11 p.m. on Oct. 23. Store employee Jee Patel said State Law Enforcement Division agents were waiting in the parking lot when workers came to open at 6…