Answer: The correct answer is "b. Either a relative or an absolute measure of poverty.".
Explanation: The poverty measure in this case has the possibility of being relative or absolute. The point is that any change in the way of measuring poverty can cause 4 million more people to be considered poor, therefore the president must support this and clarify that regardless of the change in the measurement, the 4 million people now classified as poor are the same, since this change is not a consequence of policies taken by the president, but rather due to a change in the measurement of poverty.