In the story "A Triumph of Surgery," Tricki, the overindulged dog belonging to Mrs. Pumphrey, exhibits several concerning behaviors indicating his deteriorating health. These include:
Refusing to eat his favorite food: Tricki, who usually enjoys his meals and snacks, starts refusing to eat even his favorite treats, signaling something is wrong.
Didn't go for walks: Tricki stops showing enthusiasm for walks and physical activity, suggesting lethargy or other health issues.
Vomiting: Tricki experiences vomiting, indicating possible digestive problems or other complications due to his overfed condition.
These behaviors collectively indicate that Tricki's health is in jeopardy, leading to the narrator, Mr. Herriot, taking action to address the problem. Thus, the correct answer is All of the above, as Tricki's behavior reflects a combination of these troubling symptoms.