Answer:
The correct answer is B) an increase in mandatory spending, and if not other changes are made, an increase in the government's budget deficit.
Step-by-step explanation:
Mandatory spending is the obligatory spending of the US government. It essentially consists of three social programs: Social Security, Medicaid and Medicare. It represents around 60% of total federal spending.
A decrease in the age for receiving Social Security would result in more mandatory speding because more people would be eligible for the program.
The federal goverment is currently running a deficit of almost 5% of US GDP. All else being equal, more people eligible for Social Security would increase the deficit even more.