Passage Summary: The government wants to protect seniors and the chronically ill from the flu by giving them shots every year, but since the flu strain changes annually, they'll need a new shot for a new strain every time.

Conclusion: High-risk individuals will be required to receive a vaccination for a different strain of the influenza virus every single year.

Reasoning: The government's policy targets high-risk groups for annual vaccinations, but each year's vaccine is designed only for the specific strain expected to be most common that year.

Analysis: This is a Sufficient Assumption question, so we are looking for a bridge that guarantees the conclusion is true. The argument tells us that people need a vaccine every year and that each vaccine only covers one strain, but it leaps to the conclusion that the strain will be different every single year. To make this logic airtight, we need to assume that the 'most likely' strain of the virus actually changes from one year to the next. Look for an answer choice that confirms the virus strain prevalent in one year is never the same as the one prevalent in the following year.