(A) compares the fat content of dinners eaten at home by adults who do not work outside the home to the national guidelines. (A) does not compare or provide information on the two groups in question (adults who work outside the home and adults who do not).

This does not help to explain the apparent discrepancy: the stimulus discusses dinner, not breakfast.

This does not offer a similarity that helps to explain the apparent discrepancy: the stimulus already says that adults who work outside the home spend less time on dinner, which is at the core of the discrepancy.

(D) draws a similarity between the groups, explaining that they may actually spend similar amounts of time preparing dinner at home. Adults who work outside the home eat less dinners at home, meaning the time they do spend on preparing dinner at home is spread across less meals.

This deepens the discrepancy between adults who work outside the home and adults who do not. According to (E), adults who work outside the home do less cooking and less planning, yet their homemade dinners are somehow similar to the stay-at-home group's.