Final answer:
Mandatory government spending categories covered by FICA taxes are Social Security and Medicare, which provide retirement benefits and healthcare to eligible individuals.
Step-by-step explanation:
The two mandatory categories of government spending that are paid for by FICA taxes are Social Security and Medicare. FICA stands for the Federal Insurance Contributions Act and taxes collected under this act help fund these two important programs. These programs are considered mandatory spending because they are entitlements which individuals are legally entitled to, provided they meet the eligibility requirements.
Social Security provides retirement benefits and financial assistance to individuals with disabilities and survivors of deceased workers. Medicare, on the other hand, is a healthcare program primarily for individuals aged 65 and over, as well as for younger people with certain disabilities or end-stage renal disease.
Therefore, the correct answer is option 4) Social Security and Medicare.