Final answer:
If people were allowed to choose how much money they wanted to pay in taxes, the government would have to make up the revenue through raising taxes in a different area or cutting spending. This would lead to a reduction in revenue and a potential need for cutting back spending dramatically.
Step-by-step explanation:
If the government allowed people to choose how much money they wanted to pay in taxes, the government would have to make up the revenue either by raising taxes in a different area or cutting spending. Programs where the amount of spending is not fixed, but rather determined by macroeconomic conditions, such as food stamps, would lose a great deal of flexibility if spending increases had to be met by corresponding tax increases or spending cuts.
The government would not necessarily increase welfare payments to the poor (option A) because the government would need to balance its budget. Option B, increasing the amount of public goods available, is also unlikely because there would be a reduction in revenue. Option C, cutting back spending dramatically, is more likely if the government needs to make up for the revenue loss due to fewer taxes being collected. Lastly, option D, collecting more money than under the current compulsory system, is incorrect as individuals would be paying taxes based on their own discretion.