Final answer:
The most pertinent question to ask a sick patient who recently returned from Europe is whether anyone else in their travel party is sick, as it helps identify potential outbreaks and prevent the spread of infectious diseases.
Step-by-step explanation:
The most pertinent question to ask a patient who recently returned from Europe and is now ill would be B. "Is anyone else in your travel party sick?" This question is important because it helps to determine if there might be a common source or exposure that could explain the illness, such as a contagious infectious disease that others might also have contracted. This information is crucial for public health officials and for preventing further spread of the disease. Assessing the health of the travel party can provide clues for potential outbreaks or exposure to particular illnesses that are more prevalent in certain areas.