Why are most social scientists critical of the "official poverty thresholds?" .
A. Because the thresholds overestimate the number of people in poverty
B. Because the thresholds are based upon spending 1/3 of one's income on food and the number really should be 2/3 of one's income
C. Because the thresholds tend to underestimate the number of people in poverty
D. Because poverty is a social construction that doesn't have a basis in reality