Which worm is likely to cause abdominal pain in dogs?

Whipworms are known to cause significant gastrointestinal issues in dogs, including abdominal pain. The presence of whipworms in the intestines can result in inflammation and irritation of the intestinal lining, leading to symptoms such as diarrhea, weight loss, and abdominal discomfort. These parasites are more common in adult dogs and can lead to serious health issues if left untreated.

Roundworms, while they can also cause gastrointestinal distress, are often more associated with other clinical signs such as a bloated abdomen or pot-bellied appearance more so than acute abdominal pain. Flatworms, or tapeworms, generally do not cause direct abdominal pain; instead, their presence may lead to more noticeable symptoms like weight loss or segments of the worm being found in the feces. Hookworms can cause anemia and are often associated with more systemic health problems, though they may lead to abdominal symptoms as well, they are not as directly linked to acute pain compared to whipworms. Thus, the link between whipworms and abdominal pain makes them the correct answer in this context.