Answer:
c. punish crimes and enforce voluntary agreements but not to redistribute income.
Explanation:
Robert Nozick's full statement is "Government should punish crimes and enforce voluntary agreements but not redistribute income".
Libertarianism seeks "liberty". Off course their view of liberty only includes the good parts of liberty and government; government has to provide safety and security to the population but virtually nothing else. All the rest of any government's usual tasks are considered an invasion of privacy and the rights of individuals, e.g. no public education, no public health, no public services, only taxes that cover security related expenses, etc.
