In which scenario would you expect to hear coughing?

Coughing is primarily a reflex that occurs in response to irritation or obstruction in the airways, and it commonly manifests in scenarios related to respiratory issues. In cases of respiratory distress, the dog may experience coughing due to inflammation, infection, or the presence of foreign material in the airways. This response helps to clear irritants and is often accompanied by other signs such as difficulty breathing, increased respiratory rate, or altered sounds during respiration.

The other scenarios do not typically lead to coughing. For instance, increased excitement may lead to panting or changes in heart rate, but it doesn't usually provoke a cough. A rectal examination is an invasive procedure focused on the gastrointestinal tract, and it would not directly impact the respiratory system to the extent that coughing would occur. While some dogs might cough after strenuous exercise, it's not as consistent or directly related to an underlying issue as it would be in a case of respiratory distress. Thus, the expectation of coughing aligns most clearly with the presence of respiratory problems, making that the correct choice.