NEW YORK (AP) ‘ Most retailers reported sluggish sales in March when consumers ‘ fretting about mounting economic problems ‘ limited their shopping to food and other essentials. As the nation’s merchants reported sales figures today, it was clear that shoppers remained focused on buying basics at discounters and wholesale clubs and snubbed mall-based chains for clothing and other discretionary purchases. The earliest Easter in 95 years also hurt sales. Shoppers weren’t in the mood to buy spring clothing in cold weather. Wal-Mart Stores Inc. and Costco Wholesale Corp. were among the best performers and Wal-Mart raised its earnings outlook. But March proved to be another weak month for many others, including J.C. Penney Co., Gap Inc., and Limited Brands Inc. All of them reported sharp drops in sales.