A posteriorly perforating ulcer in the pyloric antrum of stomach is most likely to produce initial localized peritonitis or abscess formation in which of the following location?

Ulcer in the pyloric antrum of stomach which perforate posteriorly produce peritonitis in the omental bursa (lesser sac). It is difficult to diagnose when perforation occur to lesser sac and patient may not have obvious signs of peritonitis. Ref: Bailey and Love's Sho Practice of Surgery, 23rd Edition, Page 1045.