What is a commonly cited critique of the Official Poverty Measure (OPM) used in the United States?
a. It overestimates poverty by counting non-cash government assistance as income.
b. It accurately reflects the cost of living across different geographic areas within the United States.
c. It underestimates poverty by not accounting for non-discretionary expenses such as medical costs and work-related expenses.
d. It adjusts the poverty threshold annually based on the consumer price index for luxury goods.