Answer:
The correct answer is Income from a job
Step-by-step explanation:
Almost every person needs a job to survive, from which they get an income. People then budget their expenses according to that income, that's why the higher the income, the more people can spend.
The other answers refer to government functions. Government has to care for its people and thefore incurrs in Health care expenses. A Government also needs to defend itself from foreign threats, that's why they spend money in the military. And in order to pay for all those expenses, goverments impose taxes on the citizens.