**Core Concept:** The question is about a patient post-operatively presenting with abdominal discomfort, bloating, absence of flatus and stools, and hypoactive bowel sounds. The focus is on understanding the possible cause of these symptoms in the context of abdominal surgery.

**Why the Correct Answer is Right:**

The correct answer, option D, is based on the patient's clinical presentation and relevant investigations like abdominal x-ray. The patient has undergone cholecystectomy (gallbladder removal surgery). Post-operatively, she is experiencing abdominal discomfort, bloating, and absence of flatus and stools. Additionally, bowel sounds are hypoactive. This suggests a potential bowel obstruction.

**Why Each Wrong Option is Incorrect:**

A. Intra-abdominal abscess (option A) is less likely as the patient has received antibiotics for prophylaxis and there is no mention of fever, signs of sepsis, or a recent abscess.

B. Intra-abdominal collection (option B) is also unlikely as there is no mention of fever, signs of sepsis, or intra-abdominal collections on imaging.

C. Hernia (option C) is a less favored choice because the question does not mention a history of hernia or surgical incisional hernia.

D. Post-operative bowel obstruction (option D) is the correct answer due to the patient's symptoms and the findings of hypoactive bowel sounds on examination. An abdominal x-ray may reveal air-fluid levels, indicating a mechanical obstruction.

E. Small bowel obstruction (option E) is a plausible cause for her symptoms, but the correct answer is D as the patient has not undergone any diagnostic/therapeutic procedure involving the small bowel.

F. Post-operative ileus (option F) is a possible cause of the patient's symptoms, but the correct answer is D as there is no mention of delayed bowel motility dysfunction or ileus.

G. Post-operative ileus (option G) is similar to option F, but the correct answer is D as there is no mention of delayed bowel motility dysfunction or ileus.

H. Post-operative ileus (option H) is a possible cause of the patient's symptoms, but the correct answer is option D as there is no mention of delayed bowel motility dysfunction or ileus.

I. Ileus (option I) is a plausible cause for the patient's symptoms, but the correct answer is D as there is no mention of delayed bowel motility dysfunction or ileus.

J. Post-operative ileus (option J) is a possible cause of the patient's symptoms, but the correct answer is D as there is no mention of delayed bowel motility dysfunction or ileus.

K. Post-operative ileus (option K) is a plausible cause for the patient's symptoms, but the correct answer is D as there is no mention of delayed bowel motility dysfunction or ileus.

L. Post-operative ileus (option L) is a possible cause of