Answer:
Sixteenth (16th)
Step-by-step explanation:
The sixteenth amendment in the United States Constitution provides the right to Congress whereby, it can levy the taxes in the form of income tax on the amount of income, without segregating it in any manner, that is in no manner it is apportioned in relation to any number or weightage of the population concerned of the state.
This amendment thereby provides for straight tax as discussed in the example.