Dunkin' Brands Group Inc. has struck an agreement with the J.M. Smucker Company and Keurig Green Mountain Inc. to sell single-serve Dunkin’ Donuts branded K-Cups at retail outlets, the company said Thursday. The deal, more than a year in the making, includes a profit sharing agreement between Dunkin’ and its operators that could yield $2,500 to $3,000 per unit, per year.