If there’s one good thing these national food holidays give us, it’s plenty of freebies. This year will mark the 79th anniversary of National Donut Day — a day with a pretty awesome past, actually. Unlike many national food holidays, Donut Day dates back decades to WWI and celebrates the women who served the fried sweets to soldiers on the front lines in France. In celebration of these ladies, here’s where to score free donuts this Friday: Dunkin Donuts Get a free donut with any drink purchase. Krispy Kreme Receive a free donut of your choice — any donut — on the house. No purchase necessary. Tim Horton’s Mention National Donut Day and receive a classic donut for free with purchase of any hot or iced coffee. Lamar’s Donuts Present this coupon to receive a free donut. Select cities are also handing out travel mugs. Cumberland Farms This East Coast chain is…